Sei

Sei is the sentient form of the Nova Dragon: Sei card and the Partner Monster to Yuji Kano. He serves as the secondary protagonist in Yu-Gi-Oh! World Stage.

Appearance
Sei is a small red and white dragon. He has bright red eyes and wears what seems to be a white scarf around his neck. He has wings that look similar to long ears that allow him to fly.

Etymology
When they met, Yuji gave him the name "Sei" to go along with his last name "Kano". The two combined form the Japanese word "Kanosei", meaning "possibility". This stems from Yuji's ideology that his dueling has endless possibilities.

Personality
Sei is very soft spoken but does not refrain from speaking his mind from time to time. He has very little confidence in himself as he often believes that Yuji could have chosen a better Partner Monster to fit him, although he is usually convinced otherwise by Yuji. Sei also treasures his friendship with Yuji above all else and will often only listen to others that Yuji has deemed trustworthy. He also has a habit of fighting with Akito Kano and Himeji Sakagami over Yuji.

Biography
Pre-Grand Duel Tournament A year before the beginning of the series, Sei met Yuji on the sacred mountain where most duelists find their Partner Monsters.

More to come later.....

Abilities
Sei, unlike other Partner Monsters, is able to transform into a smaller form of his card form and usually stays in this form. He is also able to transform into his card form with a command from Yuji. What makes Sei even more unique is that he is able to change his card form to fit into any of Yuji's six Decks.