Its an ancient tribal myth, that enemiess you slay in this life, become your slaves in the afterlife? I can remember it being part of norse mythology in modern culture?

https://www.brutenorse.com/blog/2018/4/17/an-old-norse-word-...

Thanks for the info. I'm a little confused why the killers would think their victims happen to be their enemies for the relationship towards norse mythology to be true? I could see the connection if there was a personal relationship between the killer and the victim, but not when the killers are targeting random strangers they know nothing about personally.

I think it helps to consider that the killer is likely insane and therefore not applying the amount of logic you're giving it.

I've also read some theories about Zodiac in particular that he might not have genuinely believed in that storyline either, that he was just taunting the public. Whether he believed it or not I guess we cannot know, but I would still say based on his actions he wasn't the most reasonable person on the planet.

I'm sure "random strangers they know nothing about personally" made up a large portion of the Vikings enemies.

I'd also wager that the battlefield scenario that the Viking belief was developed around would simply divide everyone into "allies" and "enemies." So a killer who sees himself as following that logic would apply the same black and white logic, their victims being enemies in some personal war.

this was also a scythian belief, and iirc some peoples of ancient mesopotamia

Many societies have believed some version of this myth. https://traditionsofconflict.com/blog/2019/7/5/eternal-subju...