Ryu Ishigori/Synopsis

History
400 years ago while living in Michinoku, the Date Providence of Japan, Ryu Ishigori gained some notoriety by having the highest cursed energy output ever recorded. These rumours interested Kenjaku but an elderly Hajime Kashimo remained skeptical.

Despite fighting many worthy opponents and meeting a good woman, Ryu was unsatisfied with his life due to never having a satisfying fight, likening it to never having "dessert". As a result, he accepted Kenjaku's offer at a second life and incarnated in the present day as a participant in the Culling Game.

Culling Game Arc
By November 12th, 2018, Ryu had managed to gain 77 points in the Sendai Colony. His high cursed energy output made him one of four players locked in a tense deadlock. One of the four, the incarnated Dhruv Lakdawalla, is killed by Yuta Okkotsu. Ryu realises that his success in sneaking toward Dhruv was due to Yuta drawing attention and that Kurourushi will strike now that the stalemate is broken. Ryu simply observes the battle between the newcomer and the cockroach curse once it appears. Yuta attempts to exorcise Kurourushi without revealing that he is capable of using Reverse Cursed Technique. Still, Ryu manages to see through his tricks and notices Yuta's incredible amounts of cursed energy.

Takako Uro manages to ambush Yuta. Ryu's impatience drives him to open fire with Granite Blast, alerting the other two players to his location and forcing Yuta to consider Ryu his top priority. Ryu is ecstatic when Yuta charges at him and is amazed when the youngster avoids his attacks and turns the fight into a brawl. As their battle intensifies, he begins to consider Yuta's extraordinary skills and concludes that he may be able to fulfill his unsettled desire. Ryu unleashes an energy blast as Uro emerges to attack Yuta, only to be surprised when she uses her cursed technique to reflect the blow back at him. Ryu becomes disappointed at Yuta's apparently limited potential until the surprising arrival of Rika, Yuta's Shikigami. While Yuta fights Uro, his summoned ally battles Ryu, deflecting his attacks and launching him over the rooftops. When Yuta and Uro arrive in the same area as Ryu, they immediately unleash their own Domain Expansion in response to his.

While Uro and Ryu's individual strategies to separate Yuta from Rika by trapping him in a Domain are successful, the shocking intervention of a reborn Kurourushi causes the collapse of all three domain barriers. This leaves Uro and Yuta temporarily unable to use their techniques to their fullest capacity while Ryu can exert the same amount of energy as usual due to his Cursed Energy Discharge. He blasts Uro, previously injured by Kurourushi, into unconsciousness with a single blow. Yuta eliminates the cursed spirit before re-approaching Ryu. The remaining combatants then initiate an exchange of energy blasts. While Yuta initially loses the advantage during their beam clash, he quickly turns the tide by having Rika provide covering fire while he moves in closer. When Ryu fires a Granite Blast at close range, Yuta redirects it into the air using Uro's technique, which he copied. As soon as Rika reaches its time limit and vanishes, the remaining two combatants engage in a brutal close-quarters battle. Ryu is ultimately defeated after taking a full blow from his previously deflected Granite Blast.

Satisfied for the first time in his life, Ryu has no issue losing to Yuta but chastises him for sparing him and Uro. Ryu immediately agrees to transfer his points to Yuta using the newly established tenth rule. Before Yuta leaves, Ryu doubts his mercy, wondering if the special grade would have killed them both if this new ruling didn't allow him to build points more quickly by sparing others.

Later on in the Culling Game, after Sukuna possesses Megumi Fushiguro, Ryu is seen on a building roof. He then feels Sukuna's overwhelming presence, calling it way too sweet. Sukuna then appears in front of Ryu. Sukuna charges Ryu, and asks him if he's going to scram or not. Before he can react, Sukuna slices his torso. Sukuna laughs and says he's impressed, since he tried to cut Ryu into three, but he turned out to be better than he expected. Sukuna apologizes for taking him so lightly, and says he won't hold back on the next one. Ryu then attempts to shoot a Granite Blast at Sukuna, but before he can shoot it, Sukuna slices his head horizontally in three parts, killing him.