Yuki (ユウキ, Yuuki) is based on an original character that was first introduced in Neo Geo Battle Coliseum.
Yuki and Ai are agents of the Federative Government of New Japan, in the NEOGEO World. WAREZ has been planning to conquer the NEOGEO World and Yuki volunteered to investigate. Ai was announced as his backup and he got frustrated with this, because he thought he would have to protect her. They entered the Battle Coliseum and eventually defeated Goodman and stopped WAREZ.
Yuki is something of a pseudo-hero. He thinks high of himself, but his personality is kinda goofy sometimes. He thinks he is the best mechanical fighter in NEOGEO World. His mannerisms are very standard superhero antics.