Some people are born to kill?

im well aware of the part their child hood plays in the role of a killer but im not talking about sensless killing like a serial killer im talking about people who are just natural "warriors" if thats what you want to call them. iv though about the whole hunter gatherer idea but what if theres a "warrior" aswell also phylosophy makes a huge difference and dont go and say all killing is wrong because lets say the vikings for example back then killing was considered glorious. i dont mean to be sexist but the majority of killers are male because its fact that women think way more emotionaly which men dont so they can make "cold" decisions. once again dont mean to be sexist