>I Thought It'd be Harem Paradise, but it Turned Out to be a Yandere Hell.
>The protagonist, Kisaragi Yuuya, is the deputy head of the local high school history research club, and the student council has spoken: show off something to the next cultural festival or kiss your club goodbye. As such, Yuuya and his three fellow club members try to create a mascot character, Izaemon, to amass appeal for the club. However what follows was something that no one could have ever predicted...

https://www.youtube.com/watch?v=03KbkO5vPkE

I wonder why this never got an English release. It looks pretty good.