Ruki likes to view and treat Yui like livestock, not only because she is a human and he a sadistic vampire, but also because in his past he was treated that way by the stronger grown-ups in the orphanage he lived in. Ayato tends to mock him for his sometimes forced intellectual manners. Without dirtying his own hands, he interacts with others as a cruel-hearted military do-S (extreme sadist). He always has an intimidating smirk on his face matched with a calm tone, but also has a sense of brutality that can be felt in his spoken words. In the sixth game LOST EDEN, Ruki's school uniform consists of the dark red school blazer with a white dress shirt and he wears a long-sleeved maroon shirt underneath. He wears it with the black plaid uniform pants and brown shoes.

His school uniform consists of the black school jacket with a white dress shirt that is slightly unbuttoned revealing a long-sleeved maroon shirt underneath and a long black tie over it. He wears the black web chokers with both outfits. He sometimes wears a long-sleeved maroon shirt with a black butterfly print on the bottom left side and wears it with black pants and a black belt. He usually wears a grey jacket with a long sleeve black shirt underneath and wears it with black pants and a brown belt. He is often seen carrying a book in his right hand. Ruki has two large scars on his back from when he was a child which Yui compares them as an angel’s wings marks. He has blue-grey eyes and also three black piercings on his right ear. Ruki is a handsome young man with short ruffled hair colored with black on top and white on the tips.

Download diabolik lovers ruki