This behavior is for his full life, we only see what has happened close which is a lot, he's fought a few dogs and hundreds of cats he's had so many injuries it's insane at the vet for treatment a few times a year he is actually great with humans but have no doubt he would fight a human to protect us if it came to it.

He does not want to be inside and he takes it out on our other cat (the fighter has always been one of two since the start) who is sick of him and we already had 2 cats disappear the 2nd we saw him aggressively chase out the garden and he was never seen again and think it's possible he did something to the 1st cat we had too.

The thing is he can be really nice but the minute he goes outside like to dominate full areas, funnily enough he doesn't bother with birds or rodents or insects.

He is well loved and doesn't want for anything but just won't stop fighting.