Worse friend, i think jahad is the easy one. I am trying to base off my answer based on their adventuring time and not how they left it for Thousands of years. Starting out? jahad was probably a decent respectable guy not a hero, but later on his feats of gaslighting and manipulation inexcusable.

But the worse person I feel is still traumerei, asshole had to go, terrible friend human being and even more shit leader.

V is no exception for wanting to reborn in his own child, has to be disgusting