For me

Félix is exhausted of sentimonsters being viewed as subhuman. Heroes are there to destroy them, crowds cheer when they're killed. If he is just a monster, then screw everyone else, he'll be a monster, they've already named him. All he cares about is protecting himself and the sentimonsters created by the Peacock Miraculous. Paris and its heroes can save themselves till he discovers that a certain look-alike is also a hero, and will be becoming the target of the last attack. Marinette had always hated Hawkmoth and Agros, so she finally put an end to it and there was no denying it on his end. He hoped nobody would miss him when he saved everyone.
An AU where people hunt down sentimonsters

All rights go to Zag and Thomas Astruc