Otonashi Kanade 
Did I Seriously Just Get Reincarnated as My Gag Character?! (Manga) Volume 3 [EPUB ebook] 

The truth behind the strange events in Yolno Forest has been revealed! Much to Nacht’s surprise, the lake she accidentally evaporated upon her arrival in this world was important after all. An ancient demon has been awakened from a long slumber under its waters. Her first order of business? Revenge on humanity!

Nacht and Aisha then join the adventurers of Free Market City in their desperate attempt to defend themselves against the demon and her army of monsters. Nacht could handle it on her own, but her beloved Aisha is tired of being treated like a child. This time, she refuses to leave everything to her mistress!