Atsui

is a shinobi from Kumogakure and brother of Samui. He was assigned to the First Division in the Fourth Great Shinobi World War.

Personality
In stark contrast to his sister, Atsui demonstrates a rather audacious and hot-headed attitude, which is evident even in the heat of battle. This impulsive temperament can often result in serious repercussions, especially during confrontations, where he is likely to impetuously charge ahead others, leaving him entirely devoid of any support.

Appearance
He has medium length light colored hair cut in an asymmetrical bowl cut style. He wears a sleeveless Kumogakure uniform along with the flak jacket. He also has bandages on his forearms, shin guards, and the kanji for tattooed on his left shoulder.

Shinobi World War Arc
As Darui solitarily confronts the resurrected Kinkaku and Ginkaku, on the western coast of the Land of Lightning, Atsui appears alongside his unusually tense sister in order to provide assistance. Attacked almost immediately by numerous Zetsu clones, he incinerates the entirety in a single instant, before impetuously charging towards the opposing brothers despite their impressive arsenal.

As the conflict continues, both Atsui and Samui are hit by Kōkinjō, resulting in their souls being drawn from their bodies through their mouths. With their respective souls subsequently severed and absorbed, the siblings are placed under a combination curse and sealing technique, where if they utter the word they've used most in their lives, they'll be imprisoned for eternity. Atsui almost falls foul of this but fortunately, his sister's swift intervention saves him, allowing him an anxious moment to contemplate what his signature catchphrase is. However, when caught in the flames of Kinkaku's ensuing attack, Atsui can't avoid declaring the word "hot", sealing his fate as he is sucked into Ginkaku's awaiting gourd.

Trivia

 * means "hot" in Japanese (in reference to temperature), in contrast to Samui's name which means "cold".