Mitsukake is one of the Suzaku Shichi Seishi (Seven Celestial Warriors of the god Suzaku) in the manga and anime series Fushigi Yuugi, originally drawn by Watase Yuu. His name is written 軫宿 where the first character is the same as the distinguishing mark on his left palm (shin - literally meaning "sadness", but here meaning "healer"). Both meanings could apply to him, though.

Alternate Name: 妙寿安(Myojuan)
Birthdate: May 7th
Zodiac Sign: Bull (Taurus)
Constellation: Crow (Corvus)
Age: 22
Height: 199 cm (6 feet 8 inches)
Blood Type: O
Siblings: none; no living relatives

Mitsukake is the second-to-last seishi that the main character Miaka, the Suzaku no Miko (Priestess of Suzaku) discovers. (Specifics on the discovery below.) He does not speak very often, as he is the most quiet and reserved of all of the seishi. He is only 22 but looks several years older than that. In part, these qualities are because he continues to mourn his love Shouka, who died of a terrible fever. Also, he has short hair that stands straight up, in striking contrast to the long hair of almost all of the other seishi. He is kind and generous, always willing to use his healing power to help someone, although he can only use it once a day and even then it exhausts him to do so. He makes Tamahome's family very happy by healing his father. His primary hobby is taking care of animals, expecially his white cat Tama who goes everywhere with him and occasionally aids Chichiri's spells.

(Major spoilers for the episodes around his discovery, but also an explanation of the importance of Shouka)

When Miaka is visiting a village near Mt. Reikaku, she falls ill with the same illness, an extremely painful lethal fever, that has been ravaging the village. The only way to save her seems to be to let Miaka die and allow Shouka, a woman claiming to have the power of resurrection, to revive her. Leaving Shouka with Miaka while they investigate Myojuan, the only healer near the village, they all sense something wrong and rush back to the village to find Shouka just about to kill Miaka herself. The demon who has caused the illness in the village reveals itself as having possessed the dead spirit of Shouka. Myojuan, who came back with the seishi, reveals himself as Mitsukake and uses his healing powers to destroy the demon, but not without hesitation. Shouka was actually his love who died of the fever, and he continues to blame himself for not being in time to heal her.

Sources: The first artbook (original Japanese) and the anime itself.