I probably already told it multiple times here.
but my earliest experience was actually a guy committing harakiri which I found erotic for some reason even if I was somewhere about 6 years old
I never associated it with pain or something unpleasant.
Just equally erotic was a magic trick where a sword is pierced through one's belly.

And later I was pretty much reading Edward Hyde children's stories about people casually getting cooked, butchered, mutilated, mutilating themselves, and dying in all ways possible and nobody relay cared about that too much.

At that time I had no clue how to masturbate so while I was getting quite aroused it was ending with nothing. Also, I had no clue what are girls for and treated them just the same as boys with extra privileges. I had no interest in them for quite some time.

More interesting is that if someone pissed me off or hurt me my fantasy was usually how I kill them in a very horrible way, and this is not only fantasy. I would really do it with great pleasure if three were no danger and consequences. I do not believe in any of that moral crap that something is wrong etc. But this is not erotic at all, just pure hatred.