Azazyel
I wonder how they're going to feel when they find out the One Eyed Black Dragon is above level 10? ( If I remember correctly, in canon Ais's dad, the Chad that he was, was level 10 or the equivalent of it. All he could do was take an eye đď¸ and that was what, 1000 years ago? That dragon is even stronger now. I can't remember if the creator of Danmachi said it would take a bunch of god's to kill it or not. I could have sworn I read that somewhere "official". )