User blog comment:B214/Volume 22 spoilers/@comment-95.90.227.198-20170206220903/@comment-9595671-20170208011247

Yeah, fanfics where Issei's living dynamite in strength are pretty common, I think it's almost a tradition by this point that it's because Issei sacrifices his Heart to Ddraig instead of his arm.

Who here wishes he had actually done that in canon? That would have been pretty cool, and by Volume 12 it technically does happen due to his new body.