Oh yeah, speaking of Asura, I think he may use his Destructor Form (which is bigger than the freakin Earth itself!!!) and use nothing but one of his fingers to "crush" them, by them I mean the ones that he's training (a.k.a. Naruto, Ichigo, and Luffy). And besides, forget about taking him head on, they'll just look for cover (which I doubt they'll be any) or..., RUN FOR YOUR LIVES!!! (Laughs), That'll be so priceless. Anyway here's their reactions as they are about to do their training.
(Asura transforms into Destructor mode.) Everyone except Asura: O____O WHAT THE MOTHERF#$%IN S#$%!!! Ichigo: THIS IS INSANE!!! HOW IS THIS SUPPOSED TO BE TRAINING!!!!!! (Asura uses one of his fingers to crush 'em.) Naruto: OH MY F#$%IN GOD!!! WE ARE ABOUT TO BE F#$%IN PANCAKES!!! Luffy: WHAT ARE GOING TO DO!!!!!! Ichigo: FORGET ABOUT THIS S#$%!!! RUN FOR YOUR F#$%IN LIVES!!!!!!!!! (Too Late) (Asura crushes them, and lifts up his finger) Ichigo: ...Uuuugggghhhh...Mmmoom...is...that...you Naruto: Ggggguuuuuuuuhhhhh...Raaaammmeeen Luffy: ...Dddduuuuggghh...Heeeaavveeenn....here...I...cooomme
So Naruto and Luffy are out cold while Ichigo appears to be very exhausted. Well they're lucky they aren't training with Asura (Asura's Wrath) though, he'll put those three right straight into the hospital for months, years even.