Janosh

An abandoned underground lab was found by a group of teens in seek of some thrill. The master of this lost place is called Janosh, seemingly out of place as this place is overrun by a countless amount of eldritch abominations that the teens have to fight against to survive.

In the end it turns out the scientists opened some portal to eldrich horrors and everyone died or mutated.

The protagonist who had a crush on his best friend(who just cares about his younger sister) got injured and lost the others and Janosh nurtured him back to health but the group thought she was an evil guy and lynched her to the protagonists horror. However, as she really was one of those eldritch creatures she came back to life and kept aiding the protagonist as she grew fond of him.

Later on turned him into one of her kind as the human body was beyond help to get fixed.