Awespec
To decide someone future characteristic based only on genetics technology or whatever, is itself wrong. Each person character depend on his/ her upbringing, environment, teaching etc . People change. Sometime cruel and dishonest person becomes good and merciful and vice versa. This novel tag is rightness. For MC killing Lionel without trying to capture in snowglobe is deflect from his morale
I see, so he made the wrong choice killing him, probably. I don't know, I think he just needed some love, to be honest. Even though he was very dangerous to let free, Leonel should've at least imprisioned him on a snowglobe. Anyways, I have the feeling that Lionel will still ressurrect and come back later in the story to become Leonel's archenemy.