Hands down favorite, no contest… Boldtusk!
In Bold, I trust.
Solid go-to guy for nearly any possible situation.
Have many second favorites as well.
Ehhh you said costumes don’t count, so I’ll leave Rigard out. He’s pretty solid on his own even without the costume, but I’ve gotten accustomed to his costumed version…
Lianna is elegantly perfect in her utter simplicity. Beautiful sniper. Nothing less, nothing more.
Wu Kong, that crazy monkey man. Wild and unpredictable, but he can do some major damage when he’s not missing 90% of his hits.
Several other honorable mentions, nearly all of whom have a usefulness… even the most useless among them can occasionally be useful. Example: Obakan. Who is basically a 5* hero with a 4* level of special skill. But even he can be moderately useful in the right situation. Mostly as a kamikaze sacrificial lamb, but hey… a win is a win, sometimes you have to break an Obakan or two to make an omelet.
Ultimately the first three major game changers for me were Melendor, Boldtusk, and Wu Kong. The three of those together carried me up from a point of feeling weak and useless in every aspect of the game, to a point to where I was actually able to survive and do some decent damage.