Sun Yu

Biodata

Feature	Value
Name	Sun Yu (孙宇)
Alias(es)	Kael; Kael'thas; Sun Yu (Earth name)
Species/Race	Saiyan; formerly human before transmigrating
Gender	Male
Affiliation	Urban Management Squad (captain); Capsule Corporation associate
Occupation/Role	Saiyan warrior, martial artist, squad leader
Status	Alive
First Appearance	Chapter 1

Power Progression

Stage / Realm / Level	Chapter	Notes
Single-Tomoe Sharingan	3	Awakens while protecting Lana against dwarf natives; grants heightened perception, vision of energy flow, and insight into enemy movements.
Preliminary ki control	5	Studies his own meridians through the Sharingan during the voyage to Earth, learning to restrain and strengthen his aura.
Time Stasis	8	Develops the ability to freeze the area around him for roughly two seconds by exhausting his energy.
Kamehameha	11	Learns the technique from Son Gohan and immediately displays overwhelming output.
Knowledge Realm / Two-Tomoe Sharingan	22	Breaks through while near death against Android 19, entering suspended animation and evolving his Sharingan.
24,000 combat power	23 25	Gains a major Saiyan recovery boost after using a Senzu Bean while near death.
95,000 combat power	28 30	Reaches this level after adapting to 50 times Earth gravity over four months.
100,000 combat power	33	Increases after consuming a Senzu Bean during the Great Ape crisis.
Controlled Great Ape transformation	33 34	Uses the Dragon Balls to make his Sharingan regulate Blutz Waves and preserve his sanity during transformation.
300,000 combat power	37 43	Catches up with Lana after a year of further training; his martial-arts foundation begins paying off.
Knowledge Realm mastery noted	37	Is described as having entered the Knowledge Realm of martial arts.

Background / History

Sun Yu was originally a human and Dragon Ball enthusiast. While on his way to help an elderly woman, he was struck by a speeding car and transmigrated into the body of a low-class Saiyan named Kael'thas, or Kael. He awakened on an unknown planet after a Saiyan mission had gone catastrophically wrong, surrounded by casualties and carrying broken ribs. His new body belonged to Lana's cousin; Lana had shielded its original owner from an attack before Sun Yu arrived in it 1.

Determined not to die with the Saiyan race on Planet Vegeta, Sun Yu chose to flee to Earth and seek training in ki control. He saved the injured Lana, then traveled with her through space for a year while studying his new Sharingan and gaining a preliminary grasp of ki 1 5.

On Earth, Sun Yu became connected to the Briefs family after saving Dr. Briefs during a bank robbery. He requested a gravity training room, acquired Dragon Balls, learned the Kamehameha from Son Gohan, and sought instruction from the Guardian, Mr. Popo, Korin, and Master Roshi 8 11 16 28.

His actions repeatedly altered events around the Red Ribbon Army. He rescued Bulma from its headquarters, destroyed the organization, uncovered Project X, and survived battles against Android 9 and Android 19. Rather than destroy Project X outright, he allowed its research to continue because he wanted strong opponents through whom he could grow 18 27.

After returning to Planet Vegeta with Lana, Sun Yu defeated the Rep Squad and converted its surviving members into the Urban Management Squad. He trained its members with Earth technology and ki techniques while preparing to escape Frieza's control 42 46.

Appearance

Sun Yu has the physique and tail of a Saiyan. On Earth, he and Lana use Earth-like names rather than their Saiyan identities 1 8.

• Possesses a furry Saiyan tail, which triggers Great Ape transformation under a full moon until he gains conscious control over it 1 32 34.
• His Sharingan manifests as red eyes marked by tomoe; his two-tomoe form appears after his breakthrough against Android 19 22.
• Wears weighted gear during training; removing it allows him to access his full combat power 10 28.
• In Great Ape form, he becomes large enough to crush an abandoned building upon landing 34.

Personality

Sun Yu adapts quickly despite initially panicking after transmigration. He is ambitious and refuses to accept the fatalism of ordinary Saiyan life, believing that hard work, understanding, and repeated breakthroughs matter more than innate battle power 1 2.

He is strategic in battle, using opponent matchups, copied techniques, time manipulation, and perception to overcome stronger enemies. He enjoys challenging fights and views life-or-death combat as the fastest way for a Saiyan to improve 3 21 25.

Although capable of ruthless violence, Sun Yu is not indiscriminately bloodthirsty. He spared dwarf natives when possible, protected Earth villagers and civilians, refused to use the Dragon Balls for personal power, and cares strongly for Lana, Bulma, Son Goku, and his followers 4 12 18 26 38 45. His behavior can also be shameless and lecherous, particularly around Lana, frequently earning her anger 5 35.

Abilities & Skills

Sharingan

Sun Yu's ocular ability grants exceptional combat perception and develops further under extreme pressure.

• Sees energy flow within living bodies and studies his own meridians to understand ki 3 5.
• Copies enemy energy blasts and improves their power through his own use 4.
• Tracks high-speed movement and identifies openings in opponents' attacks 8 23.
• Evolves from one tomoe to two tomoe after his near-death breakthrough 3 22.
• Enables him to retain sanity during Great Ape transformation after Shenron modifies its interaction with Blutz Waves 34.

Time Stasis

A Sharingan-derived time manipulation technique.

• Initially freezes the surrounding area for approximately two seconds at immense energy cost 8.
• Used to save a hostage during a bank robbery and to gain openings against Android 9 8 21.
• Evolves into a more focused single-target effect during the battle with Ace 31.
• Its duration and effectiveness are limited by Sun Yu's physical energy 8.

Ki Manipulation

Sun Yu pursues refined ki use rather than relying only on Saiyan battle power.

• Can suppress and control his combat power to avoid detection 2 5 39.
• Learns the framework of Micro-Perception, Knowledge Realm, and Empty Clarity from the Guardian and Mr. Popo 16.
• Prioritizes mental cultivation and a stable martial-arts foundation over blind power training 25.
• Uses energy blasts and sustained aerial combat 4 21.

Kamehameha

A Turtle School technique learned from Son Gohan.

• Can be charged to produce output beyond Sun Yu's base combat power 11 23.
• Destroyed distant hills during his first demonstration 11.
• Destroyed the Red Ribbon Army base and its forces 20.
• Defeated Android 19 after Sun Yu removed its energy-absorbing arms 23.
• Cannot safely be used against enemies capable of absorbing energy, as Android 9 demonstrated 21.

Great Ape Transformation

Sun Yu's Saiyan transformation, later made controllable through a Dragon Ball wish.

• Normally triggered by Blutz Waves from a full moon and increases a Saiyan's power tenfold, but causes loss of sanity 32.
• Can be activated at will after Shenron modifies his Sharingan to filter or receive Blutz Waves 33 34.
• Retains his consciousness in transformed form through the Sharingan 34.
• Copied Lana's Flame Fist while transformed and fought Lana and Ace simultaneously 34.

Leadership and Strategy

Sun Yu applies an unusually analytical mindset to Saiyan combat and organization.

• Uses a matchup strategy based on Tian Ji's horse racing against the dwarf natives 3.
• Forms the Urban Management Squad from the former Rep Squad and demands loyalty while permitting unwilling members to leave 43 45.
• Entrusts Alanks with monitoring the squad and delegates recruitment to Uncle Oli 43 46.
• Plans to use a Frieza Force expedition as an opportunity to escape Planet Vegeta and find allies 46.

Equipment / Weapons / Items

• Weighted Gear — Uses 100-kilogram weighted equipment for training; later provides sets to Oli and Hill 10 44.
• Gravity Training Room — Trains in facilities built by Dr. Briefs, eventually up to 100 times Earth gravity 9 28 36.
• Dragon Radar — Uses it to locate Dragon Balls and later to locate Bulma at Red Ribbon Army headquarters 10 18.
• Senzu Beans — Uses them to recover from fatal injuries and trigger Saiyan recovery boosts 23 33.
• Hoi-Poi Capsules — Carries equipment, including weighted gear, in capsule form 44.
• Saiyan spaceship — Used to travel from the mission planet to Earth and later return to Planet Vegeta 1 5 39.

Relationships

• Lana — His Saiyan cousin and closest combat partner. She saved Kael's original body, travels and trains with Sun Yu, and remains fiercely competitive with him 1 3 25 37.
• Bulma Briefs — A child Sun Yu repeatedly protects, beginning with the Red Ribbon Army kidnapping. She trusts him deeply and calls him her big brother 18 20 35.
• Dr. Briefs — Benefactor and ally who builds Sun Yu's Dragon Radar and gravity training rooms; Sun Yu saves him and Bulma from multiple threats 8 10 20 28.
• Son Gohan — Teaches Sun Yu the Kamehameha and later becomes Sun Goku's guardian with Sun Yu's approval 10 11 38 39.
• Master Roshi — Provides martial-arts guidance after Sun Yu visits Kame House 28.
• The Guardian — Introduces Sun Yu to the three realms of ki and later relies on him to help protect Earth 16 24.
• Ace — An android wolf created through Project X using Sun Yu's cells. Initially an enemy, he is revived by Sun Yu and turned into his training punching bag 32 36.
• Son Goku — An infant Saiyan Sun Yu finds after his early arrival on Earth. Sun Yu protects him from his Great Ape risk and leaves him to Son Gohan's care 37 39.
• Uncle Oli and Aunt Hill — Lana's parents, whom Sun Yu teaches about ki and equips with weighted gear after returning to Planet Vegeta 43 44.
• Alanks — A loyal young Saiyan appointed to supervise the former Rep Squad and assist with the Urban Management Squad 43 46.

Story Role / Major Arcs

Transmigration and escape to Earth

Sun Yu awakens as the Saiyan Kael, saves Lana, awakens the Single-Tomoe Sharingan in battle, and leaves Saiyan territory to seek Earth’s martial-arts knowledge 1 5.

Earth, Dragon Balls, and martial arts training

He allies with the Briefs family, begins the Dragon Ball hunt, learns the Kamehameha, meets Earth’s masters, and studies the realms of ki 8 16.

Red Ribbon Army and Android conflict

Sun Yu rescues Bulma, eliminates the Red Ribbon Army, discovers Project X, nearly dies against Android 19, and emerges with the Two-Tomoe Sharingan and 24,000 combat power 18 27.

Gravity training and Great Ape crisis

After reaching 95,000 combat power, he battles Ace, uses the Dragon Balls to control his Great Ape form, and ends the transformed battle between Lana and Ace 28 36.

Son Goku's arrival and return to Planet Vegeta

Sun Yu finds the infant Son Goku, leaves him under Son Gohan's care, then returns with Lana to Planet Vegeta to investigate the threat surrounding the Saiyans 37 39.

Urban Management Squad

He defeats the Rep Squad, recruits its survivors, trains Saiyans using Earth methods, and prepares an expedition that may become his route out of Frieza's control 42 46.

Trivia

• Kael'thas means “the one who brings death” in the Saiyan language 2.
• Sun Yu was an otaku and anime fan before transmigrating, with extensive knowledge of Dragon Ball and Naruto 1.
• He considers a combat power of 90,000 only an early stage of Saiyan potential and believes Super Saiyan begins beyond a base power of 3,000,000 10.
• Bulma publicly calls him “the strongest person in history” after the Great Ape incident 36.
• He chooses not to use the Earth Dragon Balls to seek immortality or power, believing Saiyan growth through broken limits is more valuable 26.