"Being weird is a religion right?"

I couldn't stop thinking about how shitty Marckus's social skills must have been after years of constant moving and living as a hunter. I imagine he might have been like, genuinely insufferable for a time... and not for no reason. Big D only cares for the hunt, and Door is anathema to the very concept of Social Cues. Without his brother, the only other constant presence in his young life would have been Horse.

Furthermore, I don't think Marckus forgot about his brother, but he did forget about the circumstances around his disappearance. I imagine he has the intelligence to know that his family has been keeping things from him, and considering that Big D likely stopped trusting Marckus after the Norfolk Island Incident, I think Marckus would start to wonder... was his brother's disappearance his fault? If that seed was planted in his mind as a child, what did it grow into as the years went by? Likely something Bitter and Resentful.

Kitten on the other hand, seems to me like the type of person to take responsibility for things that aren't even his fault. I imagine after his time in the Arcanum, he would know that discussing and studying Vampires is a huge risk. While Kitten's Character sheet has been deemed Outdated by the Ogres, we can at least assume that his family being horrifically murdered is still somewhat canon. Its very likely that subconsciously, he blames himself for their murder. Furthermore, we can also assume that the following 2 years he spent in grief-induced isolation must have done a number on him.

What I am getting at, is that Marckus and Kitten were likely vastly different when they first met compared to what they're like currently in the Chronicle.

While their apparent rivalry-turned-romance started from video games, I imagine that the key to them both moving past surface-level shared interests and Childhood nostalgia is their shared grief. Marckus being unable to remember while Kitten wants to forget.

The eventual trust and love they have now could have taken a while to get to that point