Yatsume

is a kunoichi that is taking part in Ōga's experiments.

Personality
Yatsume is quite friendly, greeting Boruto after he saved Shamo from falling to his death. When Boruto leapt back down to the crumbling floor to rescue the others, Yatsume attempted to talk him out of it, worried about him dying. When Boruto nearly failed to save himself and Shamo, Yatsume climbed down the ladder and saved his life, showing her compassion despite them having just met each other. While willing to cooperate with Boruto, she does see the merit in Batta's more selfish approach, not dismissing it immediately. She was quite emotional when she saw how much everyone wanted to survive during the "Calculation" experiment.

Appearance
Yatsume is a young girl of average height and fair complexion with big, red eyes. Her hair is black and done up in an intricate style: She has ox horns on both sides with tight braids under them and two thick antennae hanging over her face. She wears a white bandanna, a light blue, clipped-shut jack, and black shorts.

Abilities
Yatsume is a kunoichi with quick reflexes and great agility, being able to rapidly climb down a ladder and grab Boruto's hand before he could fall to his death. She could hold Boruto's and Shamo's combined weight with just one hand. She has a keen sense of smell, smelling blood on Rokuro. She has proficiency in Lightning Release, able to flowing it into her weapons.

Labyrinth Game Arc
While on the Thunder Train, Yatsume and all other passengers slept and found themselves detained in a secluded room. When she asked Rokuro about himself, noticing he was bound by seals and cuffs, Anaguma warned her to stay away from him. Then, Ōga accessed the room, claiming they miraculously survived exposure to deadly gases unleashed on the train and were brought to this facility for quarantining, and decided to put them through five experiments to test the ability to avoid death before they can leave his maze. After the "Collapse" test was chosen, the group was teleported to atop of a stone floor floating above a massive chasm. There, she introduced herself to Boruto, and the two made their way to safety. Ōga explained that the floor was very brittle and would quickly crumble, meaning they would have to escape fast. Yatsume and most of the other ninja quickly escaped by jumping to safety. Yatsume however grew concerned when Boruto went back down to help other captives. When Boruto had to save Shamo and propelled himself back up, Yatsume reached to catch them. She stood by Boruto as he criticised Rokuro for sacrificing Anaguma and Kakesu to save himself.

While waiting for the next experiment, Yatsume saw value in both Boruto's and Batta's approach to the situation, asking Rokuro his opinion. When Ōga sent them on their next experiment, she was the first to discover the candles, and listened with the group to the rules of how the candles going out killed them, and what they had to do. When the group who decided to cooperate had to force open a gate which required both hands to open, Boruto trusted Yatsume with his candle while he helped open it. In the next room, she along the other shinobi helped protect the non-shinobi from a dust storm while they protected the entire group's candles. Near the end, they had to take a slow-moving elevator, and realised that their candles wouldn't last the entire ascent, Ōga intending them to steal each other's candles. Boruto exploited the exact wording of Ōga's rules to make one long candle with the remains of everyone else's, shared by all, so they all survived the ride, clearing the experiment.

Before the next experiment, Yatsume tried to comfort Batta, but was rebuffed, so instead shared what she dreamt of doing if she escaped, in her case changing her hair colour, prompting others to share their dreams. When she tried to get Batta to share hers, she noted Batta's use of "need" instead of "want" when talking about money. When the experiment began, and the ceiling was triggered to come down on them, Yatsume injured herself attempting to stop it with her Lightning Release chains. When they managed to uncover alcoves on the walls, Boruto allowed Yatsume one spot, due to her injury and in gratitude of her saving him in the first experiment. While Boruto and others tried to break open a hidden space under the floor, Batta considered killing Yatsume to take her alcove, so Yatsume demanded to know the reason behind her death, Batta admitting she needed money to buy back her home island from rich resort developers. Boruto convinced Batta to help him, exposing a weak spot on the floor. The extra space allowed everyone to survive the experiment.

Yatsume was among those who noted that Boruto and Batta were taking a long time returning. By the time they did, the "Calculation" experiment had been picked, in which each person had a card with a number from 1 to 8 in it, and had to collect enough to sum 7 to go through a gate within two hours. Yatsume's was 4, and she met with Namua, refusing his 5 when he offered it, unwilling to take it from her friends. He showed her his conclusion that at most five people could survive the experiment, and listened to Namua talk about how he felt about his past. They were joined by Boruto and Shamo before finding Batta and Fugō's corpses. When Rokuro arrived and tried to kill everyone to reach Ōga's goal of only one survivor early, she was emotional by how much everyone wanted to live. After Rokuro's defeat, he revealed that Batta and Fugō were already dead when he claimed their cards, so Boruto shared with them Batta's suspicion of Kiseru. Yatsume and Shamo helped Namua through the gate while Boruto stayed behind to confront Kiseru.

Namua and Shamo discussed Boruto's attitude as Namua's condition worsened. Shamo went ahead to search for medical supplies, and returned with Rokuro, the three of them deciding to capture Kiseru, Namua holding the gate open for them. They joined Boruto in cornering Kiseru, but he escaped underground with his Fire Release. Chasing him, Shamo protected Yatsume with his Earth Release from falling debris in the caves. After splitting the group, Kiseru targeted Yatsume, resisting her Lightning Release, and retreating when Boruto caught up and Shamo attacked him with Earth Release. She was scared of Kiseru, and asked Boruto to stop him. Shamo checked on a scroll his attack made Kiseru drop, and they discover the nature of Kiseru's mission. Shamo went on ahead, while an injured Yatsume joined up with Rokuro, catching up just in time to see Kiseru stabbing Boruto. She was unaware that everything they were going through was a genjutsu, and that they were in suspended animation.

Trivia

 * Her name could be a shortening of yatsumeunagi, which means "lamprey".