Candy Hearts Exchange 2025
Dear Candy Hearts Person,
I am once again requesting relatively small Korean thriller fandoms :D! Assumedly that is also what you are into if you are here. Let's get into it!
General Fic Likes
Fandom specific DNW: Killing off the characters in the main ship during the fic. If you want to imply they're going to die in the future, that's okay; if you want to kill off one of the characters in these requested ships, it's fine as long as that's not the ship you're focusing on. (E.g. it's fine to kill off Jung Chung if it's a Lee Joong-gu/Lee Ja-sung fic, but please don't if it's a Jung Chung/Lee Joong-gu fic, at least not during the fic itself.)
I've watched this movie twice in the past year, and it is quite good! My favorite character is predictably Lee Joong-gu (yes, I just love Park Sung-woong) and I'm pretty much up for shipping him with anyone. Feel free to include multiple of these, even, if you want to; I just want to see Lee Joong-gu involved in some shippy business.
As a side note: dub-con and non-con are fine for any of these ships, going in either direction. As is general toxic behavior! These are simply not nice people lol.
For Jung Chung/Lee Joong-gu: It's all about the rivalry! The love-hate and the banter and the almost hitting each other with a car! Also, these two don't trust each other and yet Lee Joong-gu still appears to feel really betrayed when he thinks Jung Chung would actually turn him in to the police.
Some ideas:
-Did Jung Chung actually kill the old chairman like Lee Joong-gu seems to think? If Lee Joong-gu found out for sure that he did, what would happen then?
-Jung Chung says at one point that Lee Joong-gu is in an eternal puberty. Where did he get this idea? (...is Lee Joong-gu just constantly horny around him? Are they secretly in a relationship and constantly fucking??)
-Instead of trying to kill Jung Chung, Lee Joong-gu has him kidnapped, and when he gets out of prison, he goes to deal with him ~personally.~
-Canonically, we see Jung Chung kicking ass in a knife fight, but we never actually see Joong-gu fight physically. Which of them would win in a fight between just the two of them? (Would love one of them holding a knife to the other one's throat!)
For art: I'd love to see something adversarial. Holding each other at knife point, confronting each other in the car scene. Or any type of sexy menace :D :D
For Lee Joong-gu/Lee Ja-sung: These two honestly don't interact much in canon. But I'm a strong believer in my fave/the main character ships and this is one of those. Joong-gu originally sees Ja-sung as just Jung Chung's underling, but by the end he's able to guess that Ja-sung is the one sending men to kill him and the one who will win the board election (he doesn't for a minute imagine it will be Jang Su-ki, for example) and even congratulates him from a distance.
...yeah, that's about all the justification I can muster. I just think it would be hot!!
Some ideas:
-What if Ja-sung holds Joong-gu captive instead of trying to kill him, and brings him under control as his subordinate now that he's been elected chairman? (Maybe with some dub-con or non-con as part of the process of persuasion--or as punishment for killing Jung Chung.)
-What if Joong-gu was using Ja-sung as a double agent spying on Jung Chung? (Except that Jung Chung knew and Ja-sung was reporting it all to him (except that really Ja-sung was reporting everything to the police).) Just make this whole espionage tangle even more complicated! (And perhaps some conflicts of loyalty if Ja-sung grew to like Joong-gu?)
-What if Joong-gu tried to seduce Ja-sung just to piss Jung Chung off bc he's Jung Chung's underling?
For art: Again, any kind of confrontation, holding at knife point or the car scene is fine. Maybe art involving the identity porn aspect--Ja-sung covering Joong-gu's eyes, or Joong-gu reading papers that reveal Ja-sung's identity, or Ja-sung in a police uniform? Or art of Joong-gu's death scene (being surrounded on the couch) except now Ja-sung's there along with his men (and maybe it's shippy?).
For Lee Joong-gu/Kang Hyung-chul: I just think there was mad sexual tension here. The fuckign glares and smiles they throw at each other. The insults and banter. The implication that they've gone through this song and dance of Kang trying to get dirt on Joong-gu over and over again. The way Kang absolutely plays Joong-gu with those photographs. There's a lot going on.
Some ideas:
-Lee Joong-gu tells Kang Hyung-chul at one point that he woke him up a bit late for a booty call when Kang wants to meet him in prison. What if it actually was for a booty call?
-How did Kang and Lee Joong-gu first encounter each other? Or what kinds of conflicts have they gotten into in the past?
-What if Kang tried to get Joong-gu to turn on others in the gang in the past (especially Jung Chung) and Joong-gu rejected him?
-In terms of non-con/dub-con, maybe Kang Hyung-chul abuses his authority once he has Joong-gu in handcuffs or behind bars--and maybe he's done this in the past too, and that's why Joong-gu is so personally hostile towards him.
For art: There are some fun confrontation scenes in canon you could draw. I'd love to see Joong-gu handcuffed or otherwise restrained while Kang is being all smug. Maybe Joong-gu being arrested at the restaurant, or Joong-gu in prison? Or a ~clandestine meeting~ between the two.
I am once again requesting relatively small Korean thriller fandoms :D! Assumedly that is also what you are into if you are here. Let's get into it!
General Fic Likes
Identity porn
Crack written seriously
Hurt/comfort
Kidnapping and captivity
Bondage
Dub-con and non-con
Obsession, possessiveness
Magic AUs (Animal transformations, soulmarks and soulbonds, curses, vampires, werewolves, etc)
Different first meetings
Couples getting together
UST/pre-slash
Fix-it fic
5+1 fic
Canon divergence
Trapped in an elevator/cave/snowstorm together
General Art Likes:
DNWGeneral Art Likes:
Limited palette, especially if suited to the source's palette or colors associated with the character.
Nice backgrounds
High contrast in lighting/coloring
Jewel tones
Ink sketches/black and white
Anything from photorealistic to super stylized is fine
Short (maybe even one panel?) comics
Exaggerated expressions. (Or subtle expressions, I guess. Either.)
Couples kissing or about to kiss.
Couples sitting in each other's laps.
Couples dancing together.
Characters in a moment of high vulnerability.
Dysfunctional couples fighting or threatening each other.
People holding each other at gun or knife point.
People being tied or chained up, or behind bars
Whumpy art with characters being injured
People holding each other at gun or knife point.
People being tied or chained up, or behind bars
Whumpy art with characters being injured
Spooky stuff (dark backgrounds/settings, sense of mystery)
Note: I'm only requesting art for certain fandoms, but art treats are fine even for fandoms where I'm not requesting it.Noncanonical main character death
PWP
Eye, finger, or toe injury
Extreme ageplay
Men raping women
A focus on suicide or suicidal ideation
A focus on alcoholism
Art depicting genitalia
Tarot card art
Black Out: Goh Jeong-woo/Hyeon Geon-oh (Fic)
I love Geon-oh begging Jeong-woo for forgiveness and how Jeong-woo is kind and patient with him even while he wants to demand answers and explanations. Jeong-woo spends the whole show trying to get people to help him uncover the truth, and Geon-oh is the only person who is implicated by the truth but still willing to help him, to the extent that he would be willing to sacrifice himself. These two are both such sad and whumpable boys... I want them to make out but also I want them to just support each other and, you know, survive!
This fandom is an exception to my DNW of suicidal ideation, as Geon-oh being suicidal and self destructive is a pretty major character element. Geon-oh is also an alcoholic, so feel free to include that, but I would rather the fic not focus on his alcoholism or on an attempt to get sober. Mentioning it is fine, I just don't want the whole fic to be about it.
Some ideas:
-Literally any Geon-oh lives!fic. Suicide prevention would be great, whether by talking him down or by him just ending up in a coma instead of dead bc someone got to him in time. Just a fic where he's not dead.
-What if Geon-oh went to visit Jeong-woo in prison? Would Geon-oh reveal anything to him, or would he be too scared/controlled by his father to speak out? Seeing Jeong-woo in prison is bound to fuck with him either way (especially if Jeong-woo had recently been beaten up or something), while Jeong-woo would probably be ridiculously happy to see any of his friends other than Deok-mi.
-What would Su-oh's perspective be on a relationship between Jeong-woo and Geon-oh? It would be fun to see a developing relationship from his POV. Does Geon-oh confide in him? Does Jeong-woo ask questions about Geon-oh behind his back? Does he ever third wheel on their dates? They're kind of a trio pre-canon, so I'd be curious to see it.
-I'd love to see Geon-oh and Jeong-woo protecting each other bc they really do need protection. From being threatened with guns, being hit over the head with flowerpots and bottles, and even being kidnapped and locked up... They are very Endangered and they need someone to protect and comfort them with all the threats coming their way. I'd especially love this if whoever is attacking them wouldn't expect the other to really care enough to step in (e.g., why should Geon-oh be protecting a murderer? or why should Jeong-woo get involved in the Hyeon family's business?).
Daemuga: Ma Seong-jun/Son Ik-su (Art or Fic)
For Ma Seong-jun and Son Ik-su, I'm intrigued by the weird power dynamic between them. Ma Seong-jun is basically holding Son Ik-su back with the strength of bravado but is terrified by him; Son Ik-su speaks scornfully of Ma Seong-jun but also says to watch him and puts a lot of faith in his abilities. And they spend a lot of time in each other's company. It's a dynamic wide open for manipulation, dub-con, blackmail, threats, violence, kidnapping, all kinds of bad stuff, and I'd love to see any of that. At the same time, I think Ma Seong-jun is catnip to people with daddy issues (see: Yoon-hee looking to him for protection, Chung Dam looking for approval--both things they lacked from their fathers) and Son Ik-su has a TON of daddy issues. If he could key into that and poke Son Ik-su just the right way without making him explode (or, idk, making him explode the right way) then he could probably have a pet gangster on a leash lols. But I'm not sure he would ever figure that out.
Some fic ideas:
-I love the kidnapping hotel. What if Son Ik-su were to store Ma Seong-jun there for a while? Maybe to break his will, maybe just to get him out of the way pre-canon during the time they were at odds. Or maybe just out of pure obsession ;D
-I also love Shin Nam's era in the kidnapping hotel and him eavesdropping on Son Ik-su talking about Ma Seong-jun there. What if Son Ik-su brought Ma Seong-jun to the hotel, maybe to look at Shin Nam and see if he can bring his consciousness back? What kind of conversation might Shin Nam overhear between them? Or, if you want to go fullblown nonconsensual voyeurism, I'm here for that too.
-I love Ma Seong-jun's face paint. What if Son Ik-su does too? Or, what if Ma Seong-jun were to crossdress, as shamans sometimes do?
-Son Ik-su has a lot of unresolved business with his own father. What if he wanted Ma Seong-jun to channel him for a conversation? Would Ma Seong-jun be able to do it? (I can't even imagine which outcome would end in Son Ik-su more pissed off--on the one hand, he doesn't tolerate failure, but on the other hand, there's no way that reunion is going to go smoothly.)
-Son Ik-su is the kind of guy who decides he owns an entire section of the city and will beat you up if you either hang out there or try to move. How possessive or controlling does he get when he decides a person is his territory?
Some art ideas:
-Ma Seong-jun in the face paint and shaman get-up <3 <3 <3
-Art of the scene where Son Ik-su knocks Ma Seong-jun down and beats him up! (it's shippy to me.)
-Art of their umbrella-holding stand-off pre-canon the night of the murder
-Any art of Son Ik-su casually menacing Ma Seong-jun or looming over him ;)
The Deal: Park Min-woo/Lee Jun-seong, Park Min-woo/Lee Jun-seong/Song Jae-hyo (Fic)
I simply love those Stockholm/Lima Syndrome vibes. And whump, and manipulation, and power play. There's so much potential to play with!
I'm stealing prompts from old letters here and kind of squashing prompts for the two ships together... feel free to take any of these prompts and use them for either ship as you wish :D
Some fic ideas:
For the Emperor: Lee Hwan/Jung Sang-ha (Fic)
What can I even say about these two. What a mess. The knives, literal and metaphorical. The possessiveness and control. The angst. The tragedy. The loyalty and the betrayal. I am very open to whump or hurt/comfort for these two, as is fitting for a gangster movie. But also fix-it fic, because glld;odfihdsds;idsfodhfdkfj
Some ideas:
New World: Jung Chung/Lee Joong-gu, Lee Joong-gu/Lee Ja-sung, Lee Joong-gu/Kang Hyung-chul (Fic or Art)
Art depicting genitalia
Tarot card art
Black Out: Goh Jeong-woo/Hyeon Geon-oh (Fic)
I love Geon-oh begging Jeong-woo for forgiveness and how Jeong-woo is kind and patient with him even while he wants to demand answers and explanations. Jeong-woo spends the whole show trying to get people to help him uncover the truth, and Geon-oh is the only person who is implicated by the truth but still willing to help him, to the extent that he would be willing to sacrifice himself. These two are both such sad and whumpable boys... I want them to make out but also I want them to just support each other and, you know, survive!
This fandom is an exception to my DNW of suicidal ideation, as Geon-oh being suicidal and self destructive is a pretty major character element. Geon-oh is also an alcoholic, so feel free to include that, but I would rather the fic not focus on his alcoholism or on an attempt to get sober. Mentioning it is fine, I just don't want the whole fic to be about it.
Some ideas:
-Literally any Geon-oh lives!fic. Suicide prevention would be great, whether by talking him down or by him just ending up in a coma instead of dead bc someone got to him in time. Just a fic where he's not dead.
-What if Geon-oh went to visit Jeong-woo in prison? Would Geon-oh reveal anything to him, or would he be too scared/controlled by his father to speak out? Seeing Jeong-woo in prison is bound to fuck with him either way (especially if Jeong-woo had recently been beaten up or something), while Jeong-woo would probably be ridiculously happy to see any of his friends other than Deok-mi.
-What would Su-oh's perspective be on a relationship between Jeong-woo and Geon-oh? It would be fun to see a developing relationship from his POV. Does Geon-oh confide in him? Does Jeong-woo ask questions about Geon-oh behind his back? Does he ever third wheel on their dates? They're kind of a trio pre-canon, so I'd be curious to see it.
-I'd love to see Geon-oh and Jeong-woo protecting each other bc they really do need protection. From being threatened with guns, being hit over the head with flowerpots and bottles, and even being kidnapped and locked up... They are very Endangered and they need someone to protect and comfort them with all the threats coming their way. I'd especially love this if whoever is attacking them wouldn't expect the other to really care enough to step in (e.g., why should Geon-oh be protecting a murderer? or why should Jeong-woo get involved in the Hyeon family's business?).
Daemuga: Ma Seong-jun/Son Ik-su (Art or Fic)
For Ma Seong-jun and Son Ik-su, I'm intrigued by the weird power dynamic between them. Ma Seong-jun is basically holding Son Ik-su back with the strength of bravado but is terrified by him; Son Ik-su speaks scornfully of Ma Seong-jun but also says to watch him and puts a lot of faith in his abilities. And they spend a lot of time in each other's company. It's a dynamic wide open for manipulation, dub-con, blackmail, threats, violence, kidnapping, all kinds of bad stuff, and I'd love to see any of that. At the same time, I think Ma Seong-jun is catnip to people with daddy issues (see: Yoon-hee looking to him for protection, Chung Dam looking for approval--both things they lacked from their fathers) and Son Ik-su has a TON of daddy issues. If he could key into that and poke Son Ik-su just the right way without making him explode (or, idk, making him explode the right way) then he could probably have a pet gangster on a leash lols. But I'm not sure he would ever figure that out.
Some fic ideas:
-I love the kidnapping hotel. What if Son Ik-su were to store Ma Seong-jun there for a while? Maybe to break his will, maybe just to get him out of the way pre-canon during the time they were at odds. Or maybe just out of pure obsession ;D
-I also love Shin Nam's era in the kidnapping hotel and him eavesdropping on Son Ik-su talking about Ma Seong-jun there. What if Son Ik-su brought Ma Seong-jun to the hotel, maybe to look at Shin Nam and see if he can bring his consciousness back? What kind of conversation might Shin Nam overhear between them? Or, if you want to go fullblown nonconsensual voyeurism, I'm here for that too.
-I love Ma Seong-jun's face paint. What if Son Ik-su does too? Or, what if Ma Seong-jun were to crossdress, as shamans sometimes do?
-Son Ik-su has a lot of unresolved business with his own father. What if he wanted Ma Seong-jun to channel him for a conversation? Would Ma Seong-jun be able to do it? (I can't even imagine which outcome would end in Son Ik-su more pissed off--on the one hand, he doesn't tolerate failure, but on the other hand, there's no way that reunion is going to go smoothly.)
-Son Ik-su is the kind of guy who decides he owns an entire section of the city and will beat you up if you either hang out there or try to move. How possessive or controlling does he get when he decides a person is his territory?
Some art ideas:
-Ma Seong-jun in the face paint and shaman get-up <3 <3 <3
-Art of the scene where Son Ik-su knocks Ma Seong-jun down and beats him up! (it's shippy to me.)
-Art of their umbrella-holding stand-off pre-canon the night of the murder
-Any art of Son Ik-su casually menacing Ma Seong-jun or looming over him ;)
The Deal: Park Min-woo/Lee Jun-seong, Park Min-woo/Lee Jun-seong/Song Jae-hyo (Fic)
I simply love those Stockholm/Lima Syndrome vibes. And whump, and manipulation, and power play. There's so much potential to play with!
I'm stealing prompts from old letters here and kind of squashing prompts for the two ships together... feel free to take any of these prompts and use them for either ship as you wish :D
Some fic ideas:
-Jae-hyo and Jun-seong successfully leave the country together! Until some time later--maybe even years later--Min-woo tracks them down. I'm not sure whether I want a whole squad of men in black following him here or just him showing up alone for a quiet conversation. Either way, Jae-hyo has spent quite a while thinking Jun-seong's a murderer, so that's one element in play; their Bonnie and Clyde dynamic begins to develop some cracks, and Min-woo is here to break it wide open.
-AU where Min-woo finds out that Jae-hyo betrayed Jun-seong to the debt collectors because I don't think he ever actually learned about this in canon and I feel it would have pissed him off. Bonus points if despite this, Jun-seong somehow convinces him to let Jae-hyo live. (Maybe Min-woo was originally going to kill Jae-hyo super fast as per canon but now was slowly torturing him and was going to let Jun-seong kill him but Jun-seong didn't want to?? Idk.)
-For some reason I keep picturing time travel for this fandom. Like, if Min-woo could Peggy Sue back in time to the night he was kidnapped, what would he do then? Would he just kill Jae-hyo and Jun-seong on the spot? But he does say he can't kill Jun-seong! If he just refuses to meet them, what will happen to Jun-seong and Jae-hyo? Would he be able to stand just never seeing them and not knowing or would he want to find out and spy on them and interfere in their lives/get vengeance for things that never happened? Would he save Jun-seong from the debt collectors or let events take their course? (...what if he time traveled back but it was too late and he was already fuckign kidnapped lol)
-What if Min-woo is some kind of magical creature? On the one hand, this is why he's worth such a high ransom--he's from an old magical family/clan, a rare magical being, etc. On the other hand, it makes him a terrible kidnap victim (if he's a vampire, he keeps asking to be fed blood; if he's a werewolf, now they have to hide a wolf in the closet and he keeps almost biting them; if he's half-dragon, he keeps almost burning the house down, etc etc).
-I'd love any fic with the canonical kidnapping set-up but also I'd love to see Min-woo pull a reverse on Jun-seong and/or Jae-hyo post-canon and kidnap them right back, whether for revenge or out of some kind of obsession. Maybe he wants to prove he's better at kidnapping, even! I just want to see Jun-seong get tied up I think it would be interesting.
-Post-canon, Min-woo seeking Jun-seong out and reuniting with him. I know he said they should never meet again but I kind of got the sense he said that only after he saw how shaken Jun-seong was by everything, and maybe he really did want to become friends afterwards but felt it was something he shouldn't want. Let Min-woo get some closure! (And maybe a now-ex-con boyfriend.)
-On the smutty side of things, what if the loan sharks wanted Jun-seong to pay his loan off by becoming a sex worker instead of taking his organs? (...and what if one of his customers down the line turns out to be Jae-hyo and/or Min-woo?) For the Emperor: Lee Hwan/Jung Sang-ha (Fic)
What can I even say about these two. What a mess. The knives, literal and metaphorical. The possessiveness and control. The angst. The tragedy. The loyalty and the betrayal. I am very open to whump or hurt/comfort for these two, as is fitting for a gangster movie. But also fix-it fic, because glld;odfihdsds;idsfodhfdkfj
Some ideas:
-Any kind of whump relating to Cutter or any other rival in the loan shark industry attacking Hwan or Sang-ha could be fun! Or internal feuding. Stabbing, people getting kidnapped or tortured... there's lots of fun gangster potential.
-Obsessive possessive behavior from either or both of these characters would be great. Obviously Sang-ha is already going there, what with how he acts about Hwan's girlfriend, but he could always go further ;) and what about Hwan? In terms of possessiveness, how does he act when other people threaten his place in Sang-ha's life? I'd also love to see him stalk and spy on Sang-ha or act in various ways to manipulate him. Dub-con, non-con and power play are also fine for this ship.
-It's never decided whether Hwan killed Sang-ha's subordinate or not. What if Sang-ha decided he did, and punished him for it? (And did Hwan really do it, or not?)
-Fix-it fic: Get that boat safely docked and get those men to a hospital!! Or otherwise just contrive to let them live lol. Any kind of fic where Sang-ha and Hwan both live would be super welcome.
-Sang-ha met Hwan when he was young. What if he kept an eye on him as he was growing up, or even kept in touch and Hwan knew him? (And what if Hwan had a juvenile crush, for that matter, if possibly a resentful one?)
-Sang-ha wanted to give Hwan a car but Hwan refused it :(. What other gifts might Sang-ha try to give Hwan? I want to see Sang-ha's attempted sugar daddy era!
-I feel like every one of Sang-ha's subordinates and also the old man his boss is aware of how he feels about Hwan. I'd like to see a fic of them all trying to interfere in one way or another, positive or negative, with that relationship, and Hwan, who perhaps may not understand Sang-ha's feelings as well, learning some Information by these machinations.
New World: Jung Chung/Lee Joong-gu, Lee Joong-gu/Lee Ja-sung, Lee Joong-gu/Kang Hyung-chul (Fic or Art)
Fandom specific DNW: Killing off the characters in the main ship during the fic. If you want to imply they're going to die in the future, that's okay; if you want to kill off one of the characters in these requested ships, it's fine as long as that's not the ship you're focusing on. (E.g. it's fine to kill off Jung Chung if it's a Lee Joong-gu/Lee Ja-sung fic, but please don't if it's a Jung Chung/Lee Joong-gu fic, at least not during the fic itself.)
I've watched this movie twice in the past year, and it is quite good! My favorite character is predictably Lee Joong-gu (yes, I just love Park Sung-woong) and I'm pretty much up for shipping him with anyone. Feel free to include multiple of these, even, if you want to; I just want to see Lee Joong-gu involved in some shippy business.
As a side note: dub-con and non-con are fine for any of these ships, going in either direction. As is general toxic behavior! These are simply not nice people lol.
For Jung Chung/Lee Joong-gu: It's all about the rivalry! The love-hate and the banter and the almost hitting each other with a car! Also, these two don't trust each other and yet Lee Joong-gu still appears to feel really betrayed when he thinks Jung Chung would actually turn him in to the police.
Some ideas:
-Did Jung Chung actually kill the old chairman like Lee Joong-gu seems to think? If Lee Joong-gu found out for sure that he did, what would happen then?
-Jung Chung says at one point that Lee Joong-gu is in an eternal puberty. Where did he get this idea? (...is Lee Joong-gu just constantly horny around him? Are they secretly in a relationship and constantly fucking??)
-Instead of trying to kill Jung Chung, Lee Joong-gu has him kidnapped, and when he gets out of prison, he goes to deal with him ~personally.~
-Canonically, we see Jung Chung kicking ass in a knife fight, but we never actually see Joong-gu fight physically. Which of them would win in a fight between just the two of them? (Would love one of them holding a knife to the other one's throat!)
For art: I'd love to see something adversarial. Holding each other at knife point, confronting each other in the car scene. Or any type of sexy menace :D :D
For Lee Joong-gu/Lee Ja-sung: These two honestly don't interact much in canon. But I'm a strong believer in my fave/the main character ships and this is one of those. Joong-gu originally sees Ja-sung as just Jung Chung's underling, but by the end he's able to guess that Ja-sung is the one sending men to kill him and the one who will win the board election (he doesn't for a minute imagine it will be Jang Su-ki, for example) and even congratulates him from a distance.
...yeah, that's about all the justification I can muster. I just think it would be hot!!
Some ideas:
-What if Ja-sung holds Joong-gu captive instead of trying to kill him, and brings him under control as his subordinate now that he's been elected chairman? (Maybe with some dub-con or non-con as part of the process of persuasion--or as punishment for killing Jung Chung.)
-What if Joong-gu was using Ja-sung as a double agent spying on Jung Chung? (Except that Jung Chung knew and Ja-sung was reporting it all to him (except that really Ja-sung was reporting everything to the police).) Just make this whole espionage tangle even more complicated! (And perhaps some conflicts of loyalty if Ja-sung grew to like Joong-gu?)
-What if Joong-gu tried to seduce Ja-sung just to piss Jung Chung off bc he's Jung Chung's underling?
For art: Again, any kind of confrontation, holding at knife point or the car scene is fine. Maybe art involving the identity porn aspect--Ja-sung covering Joong-gu's eyes, or Joong-gu reading papers that reveal Ja-sung's identity, or Ja-sung in a police uniform? Or art of Joong-gu's death scene (being surrounded on the couch) except now Ja-sung's there along with his men (and maybe it's shippy?).
For Lee Joong-gu/Kang Hyung-chul: I just think there was mad sexual tension here. The fuckign glares and smiles they throw at each other. The insults and banter. The implication that they've gone through this song and dance of Kang trying to get dirt on Joong-gu over and over again. The way Kang absolutely plays Joong-gu with those photographs. There's a lot going on.
Some ideas:
-Lee Joong-gu tells Kang Hyung-chul at one point that he woke him up a bit late for a booty call when Kang wants to meet him in prison. What if it actually was for a booty call?
-How did Kang and Lee Joong-gu first encounter each other? Or what kinds of conflicts have they gotten into in the past?
-What if Kang tried to get Joong-gu to turn on others in the gang in the past (especially Jung Chung) and Joong-gu rejected him?
-In terms of non-con/dub-con, maybe Kang Hyung-chul abuses his authority once he has Joong-gu in handcuffs or behind bars--and maybe he's done this in the past too, and that's why Joong-gu is so personally hostile towards him.
For art: There are some fun confrontation scenes in canon you could draw. I'd love to see Joong-gu handcuffed or otherwise restrained while Kang is being all smug. Maybe Joong-gu being arrested at the restaurant, or Joong-gu in prison? Or a ~clandestine meeting~ between the two.