Caucasus

Caucasus is an infected Vessel who gains expressions and even a gender through the ancient disease.

Pre-series
Caucasus was unofficially the sixth member of the Five Great Knights. He died while assisting the Hollow Knight to seal the Radiance and his soul was transferred into a half-grown Vessel, which depleted half of his original size. He then used Infection to keep himself alive while making sure that the Radiance can't control him.

Main story
TBA