Mistaken Identity tag is due to Merem Solomon's Demon of the Left Arm (Or "The King of Rats" for a slightly more sucient name lol) typically posing as him hence Hansa's confusion there.

Funny art in how it ignores/bends what's truth for the sake of the punchline
In Remake only Ciel has defeated DAAs
Merem/Left isn't a named member so Hansa likely has no idea who he is
Ciel's entry isn't false but she's a pretty pious person regardless and Hansa's statement doesn't contradict her actions, when the church treats Magecraft as a tool from the Lord, sth sth King Solomon with his Divine Wisdom used demons for his magecraft so....

All that aside, looks great, nice to see fanarts of chars who never get any too