Ōga

is an elderly man who kidnaps people for his survival experiments.

Personality
Ōga is an eccentric if not deranged old man. Amoral, he is so fascinated by the concept of life and death, of how people are able to escape death, he has no qualms about putting people in peril just to see how they will react and likewise will kill people just as randomly. He likewise has no loyalty to his followers, indifferently allowing them to die for failing him. In his pursuit of researching survival instincts, he is shown to be very elaborate and methodical in his experiments.

Appearance
Ōga is a short, elderly man of heavily wrinkled, light complexion. He has a wide smile with several missing upper teeth, pupilless green eyes, scraggy white hair reaching his lower back with a long white beard. He wears brown cloths and a red cap with a yellow tongue and white wings on the side.

Abilities
Ōga is a skilled puppeteer, able to manipulate one disguised as himself from a far. He can use the Yin Release to project himself in front of people. He also is skilled in fūinjutsu and space–time ninjutsu, having set up several scrolls to warp people to new locations.

Labyrinth Game Arc
When several passengers on a Thunder Train wake up secluded in a room, Ōga introduced himself through a puppet of himself, claiming that they survived an accident and were exposed to a toxic gas. Ōga believed they had a subconscious ability to avoid death, and wished to test it. When one of the captives drew a death card, he killed them, stabbing them though their head with a puppet. Boruto attacked the puppet with Wind Release. Having made clear how serious his tests were, the first of five experiments began when a Kusa-nin angrily knocked over one of the scrolls, he accidentally activated the "Collapse" test, sending everyone to new location atop of a floor that hovered over a large chasm. Ōga explained that sections of the floor would quickly crumble away and they needed to escape to a higher, safe ledge. At the end of it, only 14 captives survived, and he congratulated them, allowing them to return and rest before the next test.

As the survivors grew restless, they realised that the Kusa-nin was actually a spy for Ōga. Ōga indifferently watched as the man was killed by Rokuro. Deciding that the survivors had rested enough, Ōga appeared before them again to let the next test begin. Rokuro chose a scroll, activating the Light test. As everyone was sent to a dark room, Ōga presented them with each with a candle. He explained that everyone's candle at the start of the test was linked to their life and that if the candle went out, they would die. He made them first struggle through a watery pipeline and then a desert-like incinerator. Finally, he had the survivors enter two slow-moving elevators, where they would have to sacrifice someone else to use their candle for themselves. Once the test ended in Boruto's elevator, Ōga was impressed by the innovation of the group to unite their candles into one, extending the group's time.