Unpopular boy is saved by a girl with powers during an xmas party

Question

I'm trying to locate a manga about a this guy who is in high school and he is not really popular, to the point his whole class doesn't invite him to their Xmas party.

At the Xmas tree, in the town square, a monster destroys it. This girl with super-powers come and saves him. A day later, the monster comes back but it turns out the guy can control it and it gets stronger the angrier he gets, kind of like the Hulk, but this one acts like a dog and is separate from him. He works with the girl with powers so that they can stop his monster that she DOESN'T know that he is controlling

The reason they have powers is due to something called magic bullets or world bullets or something like that

Answer 1

This sounds like ib: Instant Bullet by Aka Akasaka.

The psychologically destitute Kuro Fukase has been betrayed by the cruel world countless times. The only people who he could ever call family were Toiro and Iroha, the two Ayakura sisters living in an adjacent apartment, but even they would soon perish in a horrific act of arson. Now, the siblings exist as mere hallucinations in Kuro's mind as he continues to bear hatred for the world.

On one bitter Christmas Eve, Fukase's very purpose in life changes. Upon meeting the strange yet cheerful girl Sera Himeura, the dubious and alluring witch Yume Furusuna, and a strange black creature, Fukase learns that he is one of 20 "Instant Bullets": people who have been granted the power to destroy the world.

However, these living weapons do not share the same goal. Some wish to save the world, while others—including Fukase—are hell-bent on its obliteration. In a suspenseful tale of past trauma, faltering morals, and twisted romance, just what future does the world hold when the powerful Instant Bullets turn against each other?