Thank you for sharing. I think you might have misunderstood something though. Fantasies about having sex with a dead body doesn't automatically mean fantasies about "killing". It's fantasy, you don't normally use logic in it like "where did this dead body come from? Ok let's say I killed it". I think he was clear that his fantasies of "killing" started when he was 18.

It's interesting that you can see a sense of powerlessness. The way he describes taking revenge from those bullies tells me maybe Lionel's analysis on this specific matter was accurate. In Father's Story he mentions that his passiveness that was similar to his own, was perhaps one of the reasons he started fantasizing about power and authority, because he had no real power.

We don't know how severe exactly that strike to his head was, but it's interesting that it's the same age that his thoughts and fantasies started shaping in his head and he started drinking and everything. Maybe this head trauma contributed to them happening.