Thanatos for me since I like turning into an absolute death machine. I'm the type of opportunistic asshat assassin who just runs around murdering anyone who seems vulnerable. Second favorite would be Skadi, because while they may nerf Kaldr they can never nerf my laughter when I turn my back and he wipes half a team. Past that, Tyr is pretty damn fun(plus his mastery skin cards are some of the nicest looking ones there are) as is Bellona if I can survive my build's horrible early game. Number 5 would be Amaterasu because while I enjoy her when I'm doing well with her, 60% of the time I do terribly.