Free summon Grima!

Hello, I have just done my free summon and finally I have pulled a good unit for free. He is +def -spd (good ivs I think). So I'm thinking of putting him the Vengeful Fighter he has in the B, and Aether or Bonfire, but I don't know which ability to put in the A. So, what do you think? I don't have Brave Ike for his ability and neither Legendary Ike (I don't know if neither there is correct, I'm Spanish lol). And Aether or Bonfire? Thanks guys