Ware ni Cheat o ~Hazure Cheat no Shoukan Yuusha wa Isekai de Yukkuri Kurashitai~ - Vol. 1 Ch. 6

[Salfaro]

So a succubus or something?
Why is the doll princess not back though?

If it is a succubus/whatever, it could be that the perps took Real Flare somewhere else (swapping her with Succubus/whatever-Flare to infiltrate the town, and for some reason that doesn't trip the "malice sensor" if she's just sucking vitality), and then Nina went off to investigate something wrt that.

A bit odd either way that Nina just disappeared after she helped and nothing's been mentioned about it though, maybe she's just not in the room with MC at the moment.