He is voiced by Yoshimasa Hosoya in the Japanese version of the anime, and by Josh Grelle in the English version of the anime.
Fumikage is a short young boy with the head of a black bird, possibly supposed to resemble that of a crow or a raven. He has a yellow beak which is slightly hooked down at the end, thin, red eyes, one on either side of his head, and a red choker, which he rarely removes. Despite the appearance of his head, however, his body is of normal human shape, with rather fair skin. After his internship training with Hawks, Fumikage has become more muscular.
His costume consists of a robe, black, but tinted a dark purple where light hits it, that covers his entire body, only stopping halfway down his shins, and knee-high black boots. During the Joint Training Arc, it was revealed that under this cape he wears a dark t-shirt, wristbands, a pair of baggy pants, similar to the ones Bakugou Katsuki wears in his hero costume, and a utility belt with a double pin buckle.
Fumikage is a reserved, serious and focused boy, albeit noble and valiant as well. Though he does not talk very much, he will directly ignore questions or requests that seem in some way pointless (like Tenya asking him to not sit on the desk) while he talks to other people as some sort of ongoing joke. When Fumikage teams up with others, he becomes more sociable, helping his teammates out, reassuring his trust in them and thanking them for their effort.
Fumikage is fond of darkness and other related concepts, considering himself a "creature of the dark" and employing archaic-sounding speeches that end up painting him as slightly dramatic. Still, Fumikage is a bit insecure about his interests due to them being more on the arcane, fantastical side, and thus harder for others to understand or relate to.
Fumikage also possesses a great amount of humility, being aware of his own limits and understanding when it's time to back down, evidenced when he surrendered when Katsuki Bakugou forced him into a difficult position to fight back. He takes any advice he gets seriously and uses it to try and improve on his Quirk and abilities. Fumikage seems to hold a certain level of belief in the concept of fate, and thinks little about fame and idolatry, but is still prideful enough to not tolerate being looked down.