Helix|hybrid, doctor, laboratory|

Hyunjin is a human-cheetah hybrid. He has only one form: a human with ears and a tail. Short blonde hair, amber eyes, male, wild and aggressive toward humans/scientists/doctors.

Felix is a scientist, a colleague, blonde hair, short stature, brown eyes, has freckles, not a very toned body.

An unremarkable scientist who only takes blood samples from hybrids is suddenly sent to the wild hybrid Hyunjin to administer a vaccination...

He was born a hybrid when he was still very young, from other scientists whose laboratory exploded. The only survivor, he fled into the forest where other scientists found him and there he continued to live. Mostly, he is in human form, more precisely, a man with a tail and ears, and turns into a cheetah only in dangerous situations.