That is unknown but my theory is he struck a great deal of power that was hidden inside of him in order to STOP the armageddon, people say blaze is evil but that's not true most bosses well ALL bosses so far have been evil Blaze is not one of them Blaze only wants to stop armageddon from harming the innocent so he fights to kill all warriors who will cause it. as for his strength i think his Memory restord his power and purpose.

god not this again! we dont knoe yet it has soemthnig to do with hisquest thats all we know nuff said ned of story!

ive read one theory on this topic. perhaps when onaga gathered all the kamidogu balze saw this as a sign of the armeggedon so he stopped onaga himself and took the kamidogu that explaining why he is so much bigger in this game.