Gatlin holds a major, mostly unwarranted grudge against his parents. He considers them terrible parents who ruined his dream of becoming a magician, by not helping him better transition to the new culture after they moved countries (Germany or America, depending on the canon). This resentment grows when he gets his groove back and becomes successful, only for them (especially Diethard) to give him pushback.

In reality, they’re just average parents concerned that their son has let his “stardom” get to his head, and he’s at risk of burning up if he doesn’t slow down. They’re not wrong, given his overindulging in food and alcohol and the amount of scandals he’s already gotten into. They worry for both his physical and mental health, but Gatlin will have none of it, telling them off whenever they bring it up.

His treatment of them is far different than how he acts with anyone else, being much more immature and spiteful, often doing things they tell him not to do, just to rebel, like an unruly teen. He's very childish with them. He'd never want that part of him being known to the public.

Both of Gatlin's parents aren't as bad as he makes them out to be, genuinely worrying about the "new" him. With how often Gatlin criticizes them publicly, he's lucky they care enough about him to not go public about how spiteful he is. It'd ruin his "carefree clown" persona he cares so much about.

Diethard is not the best with his words, his attempts at nudging Gatlin a specific way not being too subtle, but he means well.

Letizia dotes on Gatlin, but Diethard's views take precedent, leading her to usually siding with Diethard, much to Gatlin's chagrin. She does often send him gifts, which he tends to throw out or give to someone else.

He adores how she was honest with him from the start instead of sucking up to him because he was her rich boss. They banter constantly, Gatlin normally being the butt of the jokes, and he loves it, outside of a few jokes that hit a bit too close to home (especially about his weight). He crushes on her, even after he gets married, and she technically crushes back, but knows they’d never work out, due to her being asexual and him… not being that at all. He still thinks they could work out. (They wouldn’t.)

Gatlin’s favorite employee and potentially the only woman he loves romantically. Her insults sometimes do genuinely sting him, but she’s a very needed level-head for the eccentric weirdo, one of the few people who can reign him in. Nina's the straight man to his clown, and they both enjoy their roles to the fullest. While she does genuinely love him (platonically), she will also gladly make him pay for things, knowing she can get away with it, because him tossing money around willy-nilly is all part of another big "joke" to him.

Nina does technically crush on Gatlin romantically, but she knows they'd never work out, thus rejects him at every turn. On the bright side, his constant flirting met with rejection tends to be part of their jokey straight man/funny man relationships, so it tends to not hurt Gatlin all that much. When it's part of the joke, he revels in the rejection, if anything.

Gatlin isn't super close to Ignace, but enjoys the chats they happen to have. He's not nearly as big into drama and "tea" as Igance is, but he'll try to remember anything he hears, just for Ignace's sake, sometimes using drama knowledge as bribery to get him to do stuff.

Ignace finds Gatlin to be one of the better employers he's had, given Gat's very lax and talkative: two things Ignace really likes. He talkes drama with him often.

Gatlin loves him, but more as a target to tease than a person. He does trust him a lot, and thinks he does good work.

Liam is a goody two shoes, which doesn't fit well with Gatlin's more chaotic personality, though Liam does trust that Gatlin meanas well and simply doesn't care as much about rules. He'd rather not work for Gatlin, but his own morality against lying has made him feel obligated to work for him, and Gatlin just lets him, despite knowing this. Gatlin finds it funny.

Out of all my named employees, Gatlin interacts with Mark the least, as he's too chill to be fun to mess with. He does like him, and sometimes rambles to him when upset. Knowing he's friends with Nina, he'll often talk about her with him, including his feelings and wish that they could date.

Mark is very chill, and working at the casino is just a job to him. He doesn't have much of an opinion on Gatlin one way or another except that he thinks he pays well and is quite generous at Christmas.

Gatlin doesn't know Morris particularly well, but he likes almost everyone by default, thus likes Morris. He talks to him on the job pretty often, which Morris would prefer didn't happen.

In Gatlin's main canon, Morris is NOT a Tiefling, and he's a contracted mechanic Gat occasionally hires. They don't interact much, but they get along well enough, with Morris holding some ill will towards him, simply because he's a rich idiot who wastes money as a "joke." Morris might take advantage of him on occasion, by casually mentioning some sob story (pretty emotionless about it all the while), but it's nothing too extreme.

Gat "likes" Absit, but also can't stand how passive and soft-spoken he is. He wants to "fix" him. Gatlin constantly invites himself into Absit's home, causing the man quite a lot of distress.

Despite them not liking each other, Gat interacts with his neighbor very often, determined to "fix" him, by forcing him out of his shell—just like Marius did to him, years ago. He figures it if worked on him, then it should be the same for anyone else, and they'll thank him later. Gatlin claims, even to himself, that his "bullying" is for Absit's own good, but deep down, he does take sadistic glee from it. But nooo, everything he does is for Absit's sake. He's a Good Samaritan! It's not malicious!

Gat will also often hire Absit for freelance fashion work, when he wants a new outfit, or to alter an existing piece.

Absit is soft-spoken and shy, while Gatlin is the opposite, and very forceful about it, rarely leaving Absit alone when he sees him. This makes Absit dread every frequent encounter they have.

Despite not liking him, Absit does put up with him, because he's very bad at saying 'no' to things.

Gat and her get along a lot better than him and Absit, because she's very carefree and gullible, often excitedly going along with any crazy plans Gatlin has, even if it's against her uncle. That said, Idunn can sometimes even be too much for him, given she has a lot less concerns with actual criminal acts: namely, physical attacks, property damage, and stealing. He likes her at base, but if she starts going too far, he can quickly become uncomfortable. It's a gamble.

He tries to get into her pants (because he tries to get into most people's pants), but Absit thankfully does put his foot down with that, knowing Idunn can't really consent.

Idunn loves Gatlin, because he's a big enabler, especially when it comes to messing with her uncle, Absit . He's one of her favorite people for that reason, along with him just being funny.

Unlike most of his targets, he prefers messing with Zane in more subtle ways, like doing the opposite of what Zane asks him to do, or telling a neighbor "That Lune guy would love it if you do this," knowing full well it'll irritate him. He's very much a troll, and enjoys making Zane seethe without having to even say anything to his face. He'll often feign ignorance when confronted, knowing that upsets Zane too.

The prudish Zane dislikes Gatlin at base, and utterly despises him once Gat realizes this and starts messing with him. Gat finds Zane insufferable and loves it, because that makes him the perfect "target" for his antics, without having much pushback from others. If Zane finds a way to hit Gat where it hurts (his casino, probably), they could have a mutual hatred. That'd be fun.

Gatlin likes Deems... as an easy bullying target, because the judge is both gullible and overreactive: a wonderful combination.

Once Deems loses his judge position, the two end up running into each other at a theater tryout, but Deems leaves when he notices Gat's involved. Realizing they have a shared hobby, Gat tries to genuinely befriend him, and they become actual friends, though Deems continues to play tsundere, claiming it's only because he pays for everything. Gat still bullies him, but is softer than before.

Deems initially hates Gatlin, and I'm thinking at some point, he screams "I better not see you in court!" and Gatlin figures it's some dumb threat, only later learning he's a judge, when he goes to court for a defamation case.

When Gatlin later tries to befriend him, Deems initially only bites because of Gatlin's money, but in time, they become actual friends, though Deems continues to play tsundere, claiming it's only because he pays for everything.

Liv brings out the worst in Gat; when they're together, he tends to match her levels of immaturity, leading to a lot of accidental bullying and harassment of others. They mean no harm, but do rationalize people "need thicker skin" when they get complaints.

They have zero romantic interest in each other, but Gatlin has sexual attracttion, and Liv did too, until he got fat. She still enjoys sex with him, but more as yet another joke. She makes fun of his weight a lot (in and out of bed). It makes him uncomfortable, but he grins and bears it, not wanting to be a hypocrite. He wishes the attraction was mutual again...

Liv loves Gat, because he rarely pushes back against her antics and will often join in instead. He's the ultimate immature drinking buddy.

Liv was sexually attracted to Gatlin until he got fat. Now she just finds him funny. She teases him about it all the time, which makes hi m uncomforatble.

Gatlin idolizes him to an unhealthy degree, and has adopted some of Marius’ traits: namely the never-ending confidence and trying his best to let nothing phase him. The problem stems from the fact that, unlike Marius, Gatlin does have bouts of uncertainty, which makes him feel inadequate. Little does Gatlin know that Mairus has ASPD, which makes the whole “I don’t care about others’ feelings” a lot easier.

Marius himself “loves” Gatlin, but only superficially. He thinks of every person as a complex puzzle, and his main joy in life comes from cracking these puzzles, bettering their lives through his manipulation. His intentions may be selfish, but the end result of his work is selfless. Gatlin was one of his two big projects, the other being his own husband. He would care very much if Gatlin were to die, but there’d be no empathy behind that disappointment; it’d be like his favorite show getting canceled.

Gat "likes" Morris, just as a (for now) diligent employee. He's one of his more skilled employees, already used to sneaking around and breaking into things.

In Morris' Tiefling Monochrome canon, Gat's a much more heartless crimeboss (still with a jokey side, but it's SCARIER), and there, Morris is an employee and actively despises Gat. Gat is responsible for his missing horn and damaged eye. Morris doesn't show his anger, but waits for the day he can one day torture the man in revenge. But until then, he'll quietly buy his time, and be an overall diligent employee.