Who should I rank up out of all my 5 stars?

JJMAC

Hi, I'm wondering who I should rank up out of my 5 stars.

Human Torch
Dragon Man
Diablo
Nebula
The Hood

I can take 2 of them to rank 4

awesomesauce

Yes.

JJMAC

Okay, is there anyway on how to use diablo?