Overall this is a pretty easy "hard mode". The enemy is easy to just dodge, and just focus on the special moves you need to get your kills.
The final boss is much of the same (kill a few normal characters who are easy, and he appears then beat him up and he'll summon more character, rinse and repeat).
I'd learn a character in a normal (hero mode) run of the arcade mode and then if I like the character I'd run through Legend with him.