tsugikuni michikatsu
He's from the Kimetsu no Yaiba and a former Demon Slayer from Sengoku Era.
He's appearance was nearly identical to his demon form, with the exception of the number of eyes, his prominent eyebrows, and notably less pale skin. His eyes had dark purple irises and normal, white sclera as a human. As a child, he was usually seen wearing a white kimono as opposed to the purple-and-black patterned one he is seen wearing as an adult.
He's the human form of Kokushibou.
He's also the ancestor of Muichiro Tokito and Yuichiro Tokito.
And he is Tsugikuni Yoriichi older twin brother, the strongest Demon Slayer that ever existed.