Akuma no Riddle, Hidan no Aria AA Recommendations
There are many things that are the same about both of these anime.
First off both stories have a character base of mainly females, students too.
Second, the main character is a weak girl who might have some sort of twist about her.
Third, there is a strong protagonist who is understanding and willing to protect the main character.
Finally the plot seems the same in my opinion, both take place at a school that is not the ordinary, they both have something to do with fighting, and there will most likely be a twist that changes your whole perspective of the anime