AppearanceKuze is an extremely, large young man with light skin and back-length black hair that is kept in a ponytail. His mawashi belt is red in color.
A man of few words, since he was allowed to wrestle competitively again, his single-mindedness and ability to block out any distractions help him gain clarity. He also reached a level of zen-like focus that his father achieved. However, he found the road to becoming a yokozuna lonely, until he realized many others are also on same journey as he does.
Years of being banished by his father due to lack of restraint actually steeled his resolve and his patience, so he never shows his true power, even against high school yokozuna like Tennōji Shidō. His demeanor in the ring is the same as his father. His special move: Great Serpent Cleaver, is an underarm throw, which often results in the opponent either being forced out of the ring.
Like his father, he also uses Left Arm Clamp. His best belt-hold toss grip is actually from outside and over.
District Preliminary arc
Along side Kariya Shun they attend the district preliminary bout between Onimaru and Sada Mizuki. Observing the match they discuss each individual's fighting style and the possible outcome of the match.
When Onimaru is declared the winner of the match, Kuze becomes surprised and wonders how much he trained to achieve his Hyaki Nagi move.
Later on, Kuze visits the medical room. Upon entering he knocks over Ushio until picking him up and mentioning he's heavier than he had thought.
Placing him down he asks if he's hurt anywhere. When Ushio mentions about him not taking part in matches. Kuze informs him that he doesn't compete until being irrupted by Kariya calling him. When Kuze calls him over Kariya notices who he's talking with and tells him not to waste his time with people who couldn't win the District Preliminary. Kuze mentions he doesn't mean it and he was moved by Ushio's match. When Kariya is told to stop acting cool when they weren't picked to compete at their own District Preliminary. Panicking, he says his and Kuze's names will echo in the entire country.
Kanto Newcomer Tournament arc
Sat down backstage away from the tournament's action. Kuze over hears about Kariya Shun's match against Ushio Hinomaru from two people walking past, he stands up and heads towards the match. Observing their match, Kuze is taken by suprise. Backstage afterwards, Kariya claims his sumo isn't wrong and he will win next time. Agreeing with him, Kariya throws a lioncloth at him and asks if he will fight. Kuze confirms he will after a moments silence. Asked by Kariya if he's fighting for his revenge. Kuze declines and mentions he wants to fight in a formal match. When Kariya questions if his blood was stirred up by Ushio, Kuze confirms it. Shortly afterwards, Kuze now dressed for competetion heads to the sumo ring and prepares to face Kunisaki Chihiro.
Facing Kunisaki, he enters a gorrila poistion with his hands on the ground. The matches begins with Kunisaki charging at Sōsuke from a distance, and then attempting to grapple him from behind, until Sōsuke turns around. When Sōsuke goes to grab him Kunisaki moves to the edge of the ring. Approaching him to grab ahold of him, Kunisaki prepares an under arm throw until stopped. When Kunisaki slips behind him, Sōsuke gets his arm around his body. Kunisaki attempts go for a neck throw until Sōsuke grabs ahold of his lioncloth and charges out of the ring, winning the match.
In his next match, he defeats his opponent via railroading. In the next round he prepares to face Gojō Yūma. Stood in ring facing Yūma, he then takes his stance for prepering for an intail charge. Kuze charges towards Yūma headbutting in the chest which sends him the dege of the ring. When Gojou stops himself, he approaches Kuze and lauches a strike, much to his surprise. Pushed back by his attack, Yūma proceeds to grab him by the throat. As Yūma launches a series of strikes Kuze pushes him back to the edge of the ring. When Yūma steps back to deliver another stirke, Kuze grabs his lioncloth and delivers an outside arm throw. Winning the match he leaves the ring and heads over towards Kariya Shun. As Kariya mentions he were able to advance without any problems. Kuze mentions he wants to tune his intial charge asking for a hand, as there's no way he can face his father with his current sumo.
After passing the tournament preliminaries Kuze draws the number 1 ballot to determine his place in the finals. When Ushio draws the number 2 ballot to face Kuze. He tells him that his father once told him the two of them would fight each other in the face ring. Surprised, Ushio knows his father, Kuze mentions he was by him not to fight. Ushio reveals that's what he was told also and tells him to come at him with everything he's got. As long as he's going all out he'll show him his sumo.
Stood among his team mates, he's told by his coach he has to produce results, to which he agrees. Entering the ring he bows before Ushio and then takes his stance. When the match begins Kuze delivers a strong to charge to Ushio.
- Kuze Sōsuke vs Kunisaki Chihiro (Kanto Newcomer Tournament)
- Kuze Sōsuke vs Kinoshita (Kanto Newcomer Tournament)
- Kuze Sōsuke vs Gojō Yūma (Kanto Newcomer Tournament)
- Kuze Sōsuke vs Ushio Hinomaru (Kanto Newcomer Tournament)
- Kuze Sōsuke vs Tennōji Shidō (Inter-High, Individual Champion)
- Kuze Sōsuke vs Ushio Hinomaru
- Kuze Sōsuke vs Jinou
- His blood type is AB.
- His epithet, Kusanagi no Tsurugi, comes from the sword of same name which is one of three Imperial Regalia of Japan.
- His hobby is watching TV.