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 is rather 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. He has a habit of saying the word "hot"

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
When Darui confronts the resurrected Kinkaku and Ginkaku, Atsui and his sister provide assistance. Attacked almost immediately by numerous White Zetsu, he incinerates the Zetsu before charging towards the opposing brothers. Both he and Samui are hit by the 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. Although Samui advises that he not speak, Kinkaku's attack prompts Atsui to say "hot", sealing his fate as he is sucked into Ginkaku's gourd.

Trivia

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