|Anime||Naruto Shippūden Episode #320|
Despite his young age, Yukai showed great courage and leadership skills, managing to keep calm and focused while facing certain death when he and his unit were cornered by nearly two thousand White Zetsu clones. He also greatly respects Omoi, referring to the older shinobi as "onii-san" (お兄さん), an honourific for "elder brother".
Yukai has dark red hair, with two bangs, and golden eyes. He wears a white Shinobi Alliance forehead protector and a green vest, with white cloth around the waist. Like the rest of his unit, he also carries a large scroll on his back attached to arm straps. Additionally, he wears a yellow armband with the Kumogakure insignia, which was given to him by Omoi.
Being hailed as a prodigy, Yukai, alongside his teammates, was deemed combat ready and was allowed to participate in the Fourth Shinobi World War, albeit in the role of a Supply Unit, rather than direct combat.
Yukai has been shown to be proficient in Lightning Release; being able to use a powerful combination technique, with the assistance of his unit and Omoi, which neutralised a large number of White Zetsu.
Fourth Shinobi World War: Confrontation
During the Fourth Shinobi World War, Yukai and the rest of the Thundercloud Unit, was sent to the Seventh Front in order to back up the Water Attack Raid Unit, who had been overrun by two thousand White Zetsu clones. Sometime during this, they became trapped within a large statue on the battlefield after the White Zetsu used the surrounding, poisonous red soil to create a vast smokescreen of poisonous gas. After speaking with his teammates within the statue, Yukai and the others emerge to fight the Zetsu and face their fate. In the ensuing fight, Yukai is injured, however, Omoi appears and fights alongside them. At this point, using the Lightning Release Co-Operation: Thunder Bomb technique, the group is able to neutralise and finish off the remaining White Zetsu.
- When written as 愉快, "Yukai" means "pleasant, happy".
- Yukai bears a very strong resemblance to Karui, another shinobi from Kumogakure.