Oni Juro

Biodata

Feature	Details
Name	Oni Juro (鬼十次郎)
Alias(es)	Ghost; Ten-i Oni 118 126
Gender	Male
Affiliation	U-17 Training Camp First String; Country R representative 116 240
Occupation/Role	U-17's strongest player; voluntary goalkeeper of Court Five 116 123 142
First Appearance	Chapter 116 (previously mentioned in Chapter 3) 3 116

Power Progression

Stage / Realm / Level	Chapter	Notes
Otherworld user / world-class realm	116	U-17 staff identify him as an Otherworld master who has entered the world-class realm. 116
State of Selflessness and Asura Path: Demon God	118	Goes all out against Chiba Yun Chuan, activating the State of Selflessness and his fear-inducing Demon God Asura Path. 118
Limit of Thousand Forgings	121	Reveals one gate of the State of Selflessness, concentrating his power into his hands and racket while combining it with Ghost God power. 121
Limit of Seamlessness	123	Breaks through during his loss to Chiba Yun Chuan, becoming the third documented player after Echizen Nanjirou and Chiba to comprehend it. 123
Autonomous Otherworld control	139	Under Byodoin Hōō's pressure, learns to move and control the Demon God independently. 139
Full Seamlessness Demon God	141–142	Combines Seamlessness with his full Demon God power, shatters Byodoin's Otherworld Domain, and wins their rematch. 141 142

Background / History

Oni is the strongest member of the U-17 Training Camp's First String. Despite being capable of serving as Court One's goalkeeper, he voluntarily guards Court Five instead. Before Chiba Yun Chuan's arrival, he had defeated Byodoin Hōō and was regarded as the camp's strongest player. 116 123

Head coach Mifune Nyudo selects Oni to measure Chiba's strength and explicitly orders him not to hold back. Oni initially treats the middle schooler as a serious but manageable challenger; Chiba's opening exchanges quickly force him to use the State of Selflessness, the Asura Path, and eventually his Otherworld. 116 121

Chiba overwhelms Oni's Demon God and forces him into a desperate breakthrough. Refusing to lose before the First String, Oni comprehends the Limit of Seamlessness and fuses it with the Demon God, but Chiba still defeats him at 30–0 and leaves him injured. 123 126

The defeat becomes a catalyst rather than an ending. When Byodoin returns to challenge him, Oni tests the limits of his Otherworld before fully unleashing Seamlessness. He defeats Byodoin decisively, reaffirming his place at the top of U-17. 134 142

During the match between Country R and France, Oni faces Duke Watanabe in a singles power contest. He counters Duke's destruction-based tennis with Black Axe, Light Bullet, and the Demon God Otherworld, ultimately winning the match. 240 242

Appearance

Oni is depicted as a short-haired player who usually wears a short-sleeved shirt on court. His combat states transform his presence into that of a literal demon god. 139

• His Asura Path manifests black flames and a black-armored phantom with glowing red eyes. 118
• His full Demon God Otherworld appears as a larger, more solid phantom engulfed in black flame. 141
• The Limit of Seamlessness covers him in golden light, making him resemble a Demon God in golden armor. 123

Personality

Oni is proud, direct, and intensely unwilling to accept defeat. Losing to Chiba Yun Chuan in front of the First String drives him to remember his original ambition of becoming the strongest tennis player, directly triggering his Seamlessness breakthrough. 123

He respects genuine strength and does not dismiss opponents once they prove themselves. After losing to Chiba, he recognizes him as the strongest high schooler in his own mind because Chiba was able to defeat him. 126 197

His competitive nature is paired with resilience. Even when wounded, bleeding, or fighting with a broken racket, he continues to challenge stronger opponents rather than surrendering. 139 140

Abilities & Skills

State of Selflessness

Oni can enter the State of Selflessness and has opened at least two of its gates.

• Activates the base state when Chiba's strength pushes him to fight at full power. 118
• Uses the Limit of Thousand Forgings to focus immense power into his racket and arms. 121
• Comprehends the Limit of Seamlessness, the third gate and highest realm of the State of Selflessness, during his match with Chiba. 123
• Uses Seamlessness to overpower Byodoin's World Pirate Otherworld and end their rematch in a single decisive exchange. 141 142

Asura Path: Demon God

Oni's Asura Path produces a murderous aura designed to intimidate and overwhelm opponents.

• Surrounds him in black flames and black mist. 118
• Summons a black-armored, red-eyed Demon God phantom behind him. 118
• Creates intense psychological pressure; even First String spectators retreat from the court when he activates it. 119
• Chiba Yun Chuan's Chiba Domain can neutralize the power generated by this form. 119 120

Otherworld: Demon God

Oni's true Otherworld manifests as the Demon God, sometimes described as Ghost God power.

• Enhances his physical strength, shots, and intimidation through black flames. 120 141
• Can resist the mental effects of Byodoin's World Pirate Otherworld once Oni matches Byodoin's Mental Power. 139
• Learns to move the Demon God independently under pressure from Byodoin. 139
• Creates a Demon God Domain that covers the court in black flames and instills fear in Duke Watanabe. 242
• Was overwhelmed by Chiba Yun Chuan's Chaos God King during their first match. 121 122

Black Axe

Oni's signature destructive shot, performed by chopping down with a racket covered in black flame.

• Deforms the ball on contact and sends it forward as a black, flame-trailing meteor. 137 139
• Possesses power comparable to representative techniques used by world-class players. 241
• Forces Duke Watanabe to struggle under the impact despite Duke's strength-based style. 241

Light Bullet

A golden projectile technique that Oni uses as a stronger variation of Black Axe.

• Overpowers Duke Watanabe's Duke Home Run after Duke enters Destruction King Mode. 241
• Produces court-shaking impacts, spiderweb cracks, and powerful air currents. 242

Physical Strength and Endurance

Oni specializes in overwhelming force and can endure exchanges that break rackets and damage the court.

• Returns Chiba's full-power serve with all of his strength after activating the State of Selflessness. 118
• Continues fighting Byodoin despite injuries, bleeding, and a shattered racket. 139 140
• Matches Duke Watanabe, France's “King of Destruction,” in a direct contest of power. 240 242

Equipment / Weapons / Items

• Tennis racket — Oni's primary weapon; his rackets have been broken by both Chiba Yun Chuan and Byodoin Hōō, requiring him to take a replacement racket during the Byodoin rematch. 118 139 140

Relationships

• Chiba Yun Chuan — Rival and the opponent who forces Oni to awaken Seamlessness. Chiba defeats Oni's full-power Demon God, though Oni later acknowledges Chiba as the strongest high schooler in his eyes. 123 126 197
• Byodoin Hōō — Fierce rival. Oni defeated Byodoin before Chiba's arrival, then defeats him again after Byodoin returns seeking revenge. 116 137 142
• Mifune Nyudo — Head coach who orders Oni to test Chiba without holding back and later explains the hierarchy of high-level tennis strength to the First String. 116 142
• Duke Watanabe — France's power-focused “King of Destruction,” whom Oni defeats during Country R's match against France. 240 242
• U-17 First String — Oni's teammates and observers, who regard him as their number one and are repeatedly inspired by his strength. 116 142 240

Story Role / Major Arcs

Chiba Yun Chuan's U-17 Test

Oni serves as the ultimate test for Chiba Yun Chuan upon his arrival at U-17. Their match reveals Oni's Asura Path, Demon God Otherworld, Limit of Thousand Forgings, and eventual Seamlessness breakthrough, but ends with Chiba's overwhelming victory. 116 126

Rematch with Byodoin Hōō

After recovering and growing stronger, Oni accepts Byodoin's revenge challenge. Byodoin initially dominates with World Pirate, but Oni's full Demon God and Seamlessness shatter the Otherworld Domain and secure Oni's victory. 134 142

Country R vs. France

Oni represents Country R against Duke Watanabe. Their singles match becomes a pure strength showdown, culminating in Oni's Demon God Domain and a final shot that breaks Duke's racket. 240 242

Notable Quotes

“I was able to defeat you last time, and I definitely can this time!” 137

“Byodoin, you're bound to lose!” 141

Trivia

• Oni voluntarily serves as Court Five's goalkeeper despite being strong enough to become Court One's goalkeeper. 123
• He is the third documented player to comprehend the Limit of Seamlessness, after Echizen Nanjirou and Chiba Yun Chuan. 123
• His match against Chiba leaves him unable to perform strenuous activity for several days, though his injuries are not considered serious. 126