((Sure! Thanks for the interest. Honestly it wasn’t something I had a lot of fully developed ideas about until I sat down to think this out.
Hopefully this is interesting, and please let me know what you guys think!))
I really don’t think anyone just starts with homicide. I think it builds to that. And I think with the twins once it started, it snowballed quickly. But let’s talk about other crimes first.
No one will ever convince that Luke hasn’t always been a dirty little thief. Picking pockets, keeping a box of treasures in his room, reading off people’s ID’s and library cards to Mark who always would scowl and ask him why he takes things if he doesn’t intend to do anything with them.
Mark is harder to pinpoint but I imagine he’d be mostly just interested in manipulating people and situations. Which isn’t criminal per say but also isn’t the most angelic compulsion. His weak spots are Luke and Lily but aside from them I imagine Mark was able to get whatever he wanted from anyone. Free candy in shops, free desserts in restaurants, that sort of thing, just by being cute when he was younger, and creative as he got older. Luke would have seen this and immediately done his best to emulate the ability, but he’d never be do it quite as well as Mark.
Con men would have been what they were at first. As young as 12 I can see them tricking people, taking wallets, shoplifting, together as a team. Lily wouldn’t have discouraged it, as those are the kind of skills that would be useful to her in the future. In fact she’d likely teach them tricks about not getting caught. It’s one thing to know Mark can talk them out of trouble, but it’s better be clever enough not to get into trouble in the first place.
Their violent urges are maybe a little more interesting to track.
I can see Luke at five or six or seven burning ants with a magnifying glass and throwing rocks at squirrels in the yard and taking absolute pleasure in it. For Luke I think when he finally took a life I think to him it would have been the inevitable progression. He wouldn’t have planned it, but he wouldn’t be surprised that he’d landed there.
Mark would be different. I wrote a fic about Mark accidentally killing his dog here and I think that’s how he would react to his urges at first. Mark isn’t emotional so emotional anymore, but I think that’s a tolerance that’s been built over the years, particularly after he suffered abuse at the hands of one of Lily’s suitors, something I also wrote about here. So I think the violence would sit heavier with Mark at first. He would feel it the need and urges that Luke does but he wouldn’t accept them as readily.
I imagine Luke killed first. Luke is, for all appearances, not as in control of himself as Mark is. So his first kill was probably something akin to an accident, where he got angry or overly passionate and somebody ended up dead. That situation could have been a lot of things, a bar fight, an encounter with a girl gone wrong and I imagine Luke doesn’t particularly dwell on the memory. He’s gotten better since then. It’s just something in the distant past to him. I picture him at 15 or 16, and it simply being about that inability to suppress the violence any longer.
Remember from last season with Paul and Jacob in the basement? I imagine Mark’s first kill went something like that. Only he actually followed through on it. And was a bit more willing than Jacob. Mark is always in control, he needs to be for his own mental state. Luke would know this as well and would make his focus teaching Mark to take control of these urges he has, so that he never does something he doesn’t want to do again. This probably happened when they were 16 or 17.
This discovery would have led into their ability to connect with and control people who are dead better than they can connect with people in real life. Mark may be manipulative, but people are still unpredictable and real emotions, not the shallow ones (pity, jealousy, greed, anger) he can play with so easily, are much harder to fathom to him. Luke would feel the same, but he wouldn’t really articulate this. Rather his focus would always be on the power of the situation. He enjoys the sensation of callously taking life away from those who’ve done nothing wrong. Or righteously taking it away from those who have wronged him (morality is flexible for Luke, and he bends it to suit his own needs and situations)
There’s the progression as I see it. Lots of conning and petty theft and manipulation. Playing games with people has always been what they are best at, obvious in the way they toy with Ryan and later Joe. But the violence was always there and from 15-16 on it became an ever present part of their lives, something done regularly almost as a form of stress relief for the both of them. They need it. It keeps them centered on the tasks at hand.
And as always, it’s about the both of them and how they relate to each other. It’s something they do together that also connects them. Their lack of understanding of their own emotions keeps them sometimes from direct forms of expression. So they bond over things like violent murder.
Gotta love ‘em.