User blog comment:B214/Question and Answers 6/@comment-174.50.143.11-20180312041411/@comment-29963364-20180312060255

That's actually something Issei has been struggling with in this current arc. Every fight he's been in (except his fight with Sairaorg) has been a struggle for survival, or desperately trying to protect someone/something. He's never really "fought for fun" like Vali and Crom do. So no. I would not say Issei is a battle maniac. At least not yet (potential foreshadowing).