Saints

"Saints are essentially magical girls, a perfect harmony between the monster world and the human world.

Saints can be recruited in many ways and even born into their line of work, but most are initiated.

Saints have the same non-aging prospect as monsters, in which they will stop aging as soon as adulthood is reached. They also gain the resilience of monsters, able to survive many attacks and injuries that would be fatal to humans.
They essentially start as humans, however, and because of their 'heroic' nature, they are revered by humans."

Saints were created by the gods as a means to watch over the human and monster populations in the world, after a great war broke out between the two. They always have a patron god they report to once a month, and their duties are to protect their territories, destroy abominations (monsters created from emotional energy), and keep an eye on the relationship between humans and monsters in their area.

Saints are also not restricted by gender,

That's the gist of it.