Yushiro

Yushiro is a travelling companion of Tamayo and close ally of Kamado Tanjiro. He was turned into a Demon by Tamayo.

Personality
From his first appearance, it is evident he has a short temper and holding an arrogant attitude, looking down on most around him. His first conversation with Tanjiro even begins with him insulting Nezuko for being an eyesore. He is usually depicted with a scowl on his face and rarely seen smiling unless when speaking about or admiring Tamayo, whom he is in love with. He only cares for Tamayo and hates when others get in the way of his spending time with her and dislikes not being by her side for even a minute. In fact, he cares so little for others (and only for Tamayo) that while Tanjiro and Nezuko were fighting two demons who were trying to kill them, Yushiro suggests to Tamayo that they use Tanjiro and Nezuko as decoys to run from the demon, a suggestion that horrifies Tamayo. Though Yushiro claims he was joking to appease her, it is evident he genuinely considered it. He hates when others get too close to Tamayo, express even the smallest bit of attraction, or he perceives that someone insults her. He himself tends to fawn over her a great deal. He seems to be insulted when Tanjiro suggests that all demons have a hard time controlling their desire to feast on humans, asking Tanjiro if he thought all demons were that bloodthirsty to him. Despite this, he can show respect towards others, as he did take back his comment about Nezuko being an eyesore and called her pretty and also covered Tanjiro's mouth to prevent him from inhaling Tamayo's perfume, which is poisonous to humans.

History
Yushiro was human who was under the care of Tamayo as she was practicing as a medical practitioner. He was in frail state fighting a disease when Tamayo gave him the choice of succumbing to his illness or to live longer as a demon. He agreed to become a demon and has since stayed by Tamayo's side serving as an assistant as well as her guard.

Tamayo
Yushiro is in love with Tamayo and is willing to do anything to protect her. He finds Tamayo very beautiful. He is very obsessed with her and will attack and insult anyone who comes near her but him.

Trivia

 * If someone tells Yushiro "You like Tamayo-san, don't you!", he gets super red and quiet.