The school is about learning how to defeat some kind of 'demons' or aliens(can't remember the actual name) by using their special abilities.
A typical shonen boy was chosen as class leader
A cute girl with pink hair who assists him is shown as a mind reader. She seems interested in the class leader.
Shonen boy vows to protect everyone.

Shocker! Shonen boy was pushed by the cute girl off a cliff and it's revealed that this cute girl is the real main character.

Cute girl kills other students one by one because these students are the 'demons'. It's revealed that Cute girl doesn't have any powers and is using her observation & analysis skills to fool everyone that she is a mind reader. Her actions seem to be state-sanctioned.

Only a few students suspect her, one of them is an immortal boy who's pretty sharp...
Other than the class leader, she has killed a necromancer, a person who can photograph the future, a poison user...

Edit: Actually not too sure if Shonen boy was the class leader or said he would be helping the cute girl since he does get killed within the 1st chapter...I do remember that cute girl becomes the class leader because of her 'mind reading abilities'...

Please help me find this title, it's bothering me!

Munou na Nana

Ohmigosh, Thank You! 😁