Like how the story started off with KDJ as YJH's reader and YJH as KDJ's protagonist that gave him a reason to keep living. And toward the end of ORV, YJH became the reader of KDJ's life and KDJ, in turn, was the protagonist that gave YJH a goal to keep surviving for.

As KDJ read TWSA, YJH filled multiple different roles throughout KDJ's life: a father figure, a brother, and his first/oldest friend. While YJH (and other YJH variants like SP) admitted that OD filled the role of his "parent" (aka his point of origin), and his sponsor was first/oldest companion, as seen in 0th Regression.

Then we have KDJ "I am YJH"-ing his way through multiple situations, before and during the apocalypse. With YJH also wondering what KDJ would do/employing his methods when in situations where he knows his usual MO (brute force) wouldn't work, like when facing off against SP.

Plus, the most obvious cases of them literally assuming the other person's identity, like KDJ with the Prophets and both of them when in the 73rd Demon Realm.

While pivotal moments for IvanTill are associated with night and darkness.

The light they're depicted in as pairings really highlights the circumstances of their childhoods and the tone of their respective backgrounds.

Mizi is one of, if not the best, treated humans in Anakt Garden and these positive conditions reflect in her positive attitude/disposition.

Ivan, Sua, and Luka are all treated like commodities by their owners. Sua was basically a dress-up doll. Luka and Ivan are status symbols/cash cows. Their wants and needs as human beings are ignored in favor of their owners' desires, but they at least seem to regularly be given the basics requirements (food/hygiene, etc) and maybe even superficially spoiled for their seeming cooperation with their alien captors. They are likely to follow along with their owners' wishes in order to avoid possible punishment.

Till, on the other hand, is actively abused in pretty much every way possible. He's also used as a test subject by the aliens. He thrashes at the chains that bind him and we constantly see the consequences he endures for his rebellious actions.

MiziSua's relationship is framed as pretty lighthearted in the flashbacks despite humanity's present situation, mainly because half the pairing (Mizi) is unaware of how bad things actually are. She's been shielded from the reality of it by everyone around her. No one wanted to dim her light. But, of course, once she lost Sua (her God, her universe), she discovered how harsh this world truly is.

IvanTill, on the other hand, both have always seen this world for what it is. They just cope with it in very different ways. Ivan, by keeping his head down, following orders to the alien's faces, then disobeying secretly behind their backs. Till, by pushing back violently and fighting aggressively against the injustices he's faced with.

This also sort of explains why Ivan and Till both have unrequited feelings for the people that they do. Till represents hope to Ivan through his rebellious nature, his fighting spirit, that Ivan lacks. Mizi represents hope to Till with her positivity/optimism since all of his own has faded away through his years of suffering. They both are admired traits that they wish they had themselves, that they treasure in the other person.

Complete

[Teleporting ■■…] by Agentin_VV; Rated: Gen, 1,190 words; Little (past) Lee Sa-young gets teleported to (present) Cha Eui-jae and they have a short but nice reunion.

Dream-like Disaster by Anonymous; Rated: Mature, 5,346 words; A dungeon that spits out distorted versions of hunters broke out and now J, the Top 1 Hunter in South Korea, is not spared from having a version of him that embodied his negative emotions.

The Memorial Dungeon by Anonymous; Rated: Teen, 71,541 words; Reaction fic - Cha Eui-jae and many others suddenly find themselves in a memorial dungeon where they watch The Hunter's Gonna Lay Low.

What's Going On? by Anonymous; Rated: Gen, 2,824 words; AU wherein the Hunter ranking updates immediately when there is a change in ranks instead of only once a year.

The Time Where You Belong by cndlslb; Rated: Gen, 9,092 words; Lee Sayoung enters a strange dungeon and somehow ends up spending his days beside sixteen-year-old Cha Euijae instead.

Your Toes Dance Too? by GholdiLocks; Rated: Teen, 2,867 words; Cha Eui-jae's toes wiggle to good music.

Thaw my mind by Mihaaa; Rated: Gen, 5,246 words; It’s snowing outside and Cha Eui-jae falls eerily silent with a troubled look in his eyes. Sa-young isn’t sure why this is happening, but he’s willing to do whatever it takes to make his hyung as comfortable as possible.

Obsession by Nawuuu; Rated: Teen, 4,567 words; Lee Sayoung's obsession with Cha Euijae throughout the timelines.

[comic] Afterwards by ripelychee; Rated: Gen; Fancomic - that time in the rift Sayoung talked about what they'd do after the apocalypse and then some.

[comic] Live Quietly by ripelychee; Rated: Gen; Fancomic - some backstory for Eui-Jae's awakening and Sa-Young's thoughts on it.

[comic] Memorial Dungeon by ripelychee; Rated: Gen; Fancomic - domestic fluff loosely based on what I remember of the memorial dungeon chapter.

Limerence by sasugab; Rated: Gen, 2,308 words; He remembers a comfortable house and a framed photo by the beach. He thinks of wearing an apron and cooking for his hyung. He thinks of mornings with Cha Eui-jae right by his side as his husband, having the ring to back up the claim.

Will You Leave Me, Again? by SeoJunHo; Rated: Gen, 1,886 words; While Cha Eui-Jae was working in the Hangover Soup Restaurant, he encountered Lee Sayoung who began acting odd…

If I Can't Be There by wicker_writes; Rated: Teen, 1,393 words; 1st TL 240J - Cha Eui-jae is too far from home to make it back for the night so he calls Lee Sa-young so he can at least fall asleep to his voice.

Just for One Day by wicker_writes; Rated: Teen, 2,718 words; 1st TL 240J - Cha Eui-jae requested his first day off in over a year when he gets a house call from Jung Bin to request he clear a dungeon. Lee Sa-young isn't interested in letting his husband go when he desperately needs a break, and will do what he can to keep him home.

My Tears From Your Eyes by wicker_writes; Rated: Teen, 1,499 words; In a meeting of top hunters detailing Prometheus's experiments, Lee Sa-young is surprised to find J crying. His immediate concern becomes comforting Cha Eui-jae despite anyone else in the room.

White Canvas by Yazashimura; Rated: Teen, 5,269 words; What if Cha Eui-jae didn't come out of the West Sea Rift without his memories fragmented? Eight years spent wandering in a desolate, ruined world alone leave unerasable traces on Cha Eui-jae. Since escaping the rift, Cha Eui-jae could barely find the strength to remain tethered to reality. Thankfully, he is not alone, and ever dedicated, Lee Sa-young always will be by his Hyung's side.

By Your Side, Always by Yue_240J; Rated: Teen, 2,491 words; In a dungeon that reveals the past of the one he loves most, Lee Sa-young witnesses Cha Eui-jae’s burdens. Rushing home after the Dungeon of Reveries, he finds his hyung, Cha Eui-jae, missing…

Ongoing

Brick By Loving Brick by Anonymous; Rated: Teen; Despite his death 8 years ago, J constantly reminds South Korea of his presence, with his sudden and mysterious appearance in the rank. The bright red crack above the sea reminded Lee Sa-young of a hope he had long held to. Cha Eui-jae is reminded of his promise.

[Commemorative Dungeon: Memories, born from the future] by Giane0404; Rated: Teen; Reaction fic - After the reclassification, the hunters find themselves trapped in a memorial dungeon where they can react to moments in the future.

Ash Like Snow by Hezaia; Rated: Teen; Lee Sa-young arrives slightly late, or rather just in time to see Cha Eui-jae take down a certain Rift Boss. Strong, yes. Stable, no. Stubborn? Absolutely. Fortunately, Lee Sa-young is all that and also strategic.

His Respite by Keeppfkerh; Rated: Gen; Reaction fic - The day all hunters in Seoul was transported to a memorial dungeon to watch J's past and future through all timelines.

Pierce my heart and cradle the pieces by Mihaaa; Rated: Teen; Cha Eui-jae is only one year older than Lee Sa-young when he saves him.

The Path of Memories by missmaesama; Not Rated; Reaction fic - The group ventured into J's memory lane, witnessing fragments of his past and glimpses of his future. Cha Euijae is not amused.

Rift Breaker by Mixcinn; Teen; What if instead of Cha Eui-jae being dropped in a dumpster after defeating the final boss in the West Sea rift, the West sea rift opens up again instead and that’s how he escapes. Basically a more mentally drained, and feral Cha Eui-jae, where he behaves more like the monster in the rift, and has to readjust to hunter society with the help of the top hunters in Korea.

A Glimpse of the Future by NikkoLily; Not Rated; Reaction fic - The system's sudden offer to join 'reaction room' caught everyone off guard. The awakened couldn't turned down the rewards that come with it so they agreed.

One-sided Reunion by NikkoLily; Not Rated; When J just got out of the rift, instead of going into a hangover soup restaurant, he stumbled upon Lee Sa-young beating some guy up.

Between Spotlights and Shadows by sasugab; Rated: Teen; Modern AU - If someone told Cha Eui-jae three years ago that he would be making out with Lee Sa-young inside their preparation room during a concert break, he’d most definitely scoff at the idea and think they were insane.

In a Field Of Dandelions, Wishing On Every One by Sereneabyss; Rated: Teen; Cha Eui-jae woke up in a dumpster with no memories of his previous life. Trying to navigate a world filled with Hunters and Rifts while hiding from the constant regular customers at the Hangover Soup restaurant that he was an unregistered awaken was already bad enough… And then Lee Sa-young entered the picture, making everything exponentially more difficult.

Imagine the KimCom shenanigans:

LHS can get pretty awkward/shy at times around KDJ because he's a "woman". Especially when he's naked after his death on the Night of the Prophets. KDJ is confused because LHS was only like this around girls in the novel, so he thinks it's strange that he's acting this way around him.

LGY initially addresses KDJ as "noona", but KDJ just corrects him by saying "hyung". And LGY is just like *shrug* "okay hyung." And neither of them ever brings up the origin of the misunderstanding.

YSA is confused because she's been seeing KDJ clearly as a woman since the scenarios started. But for some reason half the time in her head she thinks of KDJ with "he/him" pronouns and can't figure out why. Until she becomes employed as a librarian anyway.

JHW is even more protective of this KDJ because he keeps drawing attention from unsavory men that he doesn't seem to understand the cause of (because he doesn't know everyone around him sees him as a female). JHW can't believe how unprepared KDJ always acts when this kind of harassment comes up. Honestly, it's like KDJ's never been a woman in a toxic work environment...

LJH keeps addressing KDJ as "ahjumma" and KDJ just thinks she is being a rude, moody teenage. But she does show more outward favor toward KDJ in this AU because, by her own admission, she is "weak for cool older unnies."

SYS is like LGY and LJH where she calls KDJ "ahjumma", KDJ corrects her with "hyung", and she compromises with "ahjussi". At this point KDJ is starting to get suspicious why every new person he meets addresses him with female pronouns at their first meeting.

When HSY is asked by KDJ about his looks. She says somewhat sarcastically, not really understanding the root cause of the question, that he is a "pretty woman". KDJ is devastated by this blow to his manly self-esteem.

YJH is a little less in denial about his feelings for KDJ in this AU because he doesn't have the initial "this is another man" hang up. But he will have that crisis about it later, after having already admitting his feelings to himself, when KDJ is finally able to clear up the misunderstanding with KimCom.

JHY accepts everything just fine, but she does think KDJ is a huge hypocrite for messing up her pronouns when he's always correcting people about his.