Saiki Kusuo

Biodata

Feature	Value
Name	Saiki Kusuo (齐木楠雄)
Alias(es)	Saiki; Shen He's Servant
Species/Race	Psychic / esper
Gender	Male
Affiliation	Shen He; Chaldea
Occupation/Role	Five-star ultra-rare Servant; Shen He's defensive psychic support
First Appearance	Chapter 3

Power Progression

Stage / Realm / Level	Chapter	Notes
Level 1	6	Arrived in the Marvel world heavily weakened by the Summoning System. His abilities required Enhancement Stones and mana to improve.
Level 2	18	Had regained enough power that ordinary people and conventional weapons could not threaten him directly, though defending Shen He remained more difficult.

Background / History

Saiki Kusuo was an extraordinarily powerful psychic whose abilities made ordinary experiences—such as danger, pain, and emotional excitement—difficult or impossible for him to feel. He considered sealing his powers, avoiding attention, and staying out of other people's affairs his guiding principle; when serious, he claimed to possess thirty-four ways to destroy humanity instantly 4.

He initially rejected Shen He's cross-world summons, refusing any role as a hero or Demon King. Shen He changed his mind by offering four servings of premium coffee jelly, prompting Saiki to accept the contract and arrive in the Marvel world 3 4.

The summoning sharply weakened his powers. His Mind Control failed to normalize his sudden appearance and unusual features, while his teleportation repeatedly sent him only about two kilometers away instead of to the isolated destination he intended 5. He discovered he had been reduced to Level 1 and could only be enhanced through Beginner Enhancement Stones supplied by Shen He's system 6.

Although he can return to his home world and travel through time to the moment he left, Saiki remains available for Shen He to summon in emergencies. He eventually accepts Shen He's promise to help him learn to control his psychic powers more precisely 13 24.

Appearance

Saiki is a pink-haired young man who typically wears green clothing. His conspicuous antenna-like suppressors and glasses immediately draw attention when his weakened Mind Control cannot conceal them 5 16.

• Pink hair 4 16
• Green clothing 16
• Antenna-like psychic-power suppressors on his head 5 8
• Glasses used to conceal his petrification ability 4
• Usually expressionless and reserved 5 17

Personality

Saiki intensely values anonymity, quiet, and the ordinary life of a high-school student. His weakened telepathy is, in one respect, a relief to him because it reduces the constant noise of other people's thoughts 4 7.

He dislikes flashy attention-seekers and has little patience for trouble, initially finding Tony Stark unpleasant because of his showy personality 17. Nevertheless, he is protective of Shen He and repeatedly chooses to help despite wanting to return home and avoid involvement in the Marvel world's conflicts 14 19 35.

Saiki is deeply unwilling to kill. Because taking a life would be effortless for him, he considers killing especially frightening and asks Shen He to keep him in a defensive role whenever possible 35.

Abilities & Skills

Telepathy

Saiki communicates directly through others' minds and can read their surface thoughts.

• Learns Shen He's circumstances and the Summoning System's basic information through Shen He's thoughts 6.
• Detects that S.H.I.E.L.D. agents are waiting for Phil Coulson 7.
• Can read surface thoughts, but cannot see what lies deeply within a person's heart 9.
• His telepathic range was substantially reduced after being summoned, which he finds peaceful 7.

Telekinesis

Saiki can manipulate objects, people, and attacks with psychic force.

• Restrains monsters so Shen He can kill them for experience 12.
• Instantly crushes large numbers of dungeon monsters 12.
• Creates a psychic barrier that stops a skidding ambulance before it hits pedestrians 13.
• Halts bullets in midair and suspends a Hydra assassin 14.
• Knocks warehouse guards unconscious without triggering an alarm 37.
• Opens a summoned sack and restrains Violet when she attacks Tony Stark 29 31.

Teleportation

Saiki can relocate himself and others instantly.

• Teleported into space in an attempt to escape the summoning request 4.
• Initially could only travel roughly two kilometers due to his weakened state 5.
• Brings Shen He into dungeon instances and hostile facilities 10 37.
• Uses teleportation to evade danger, move allies, and cut apart Ivan Vanko's whips 17 41.

Clairvoyance

Saiki can remotely perceive distant locations and hostile forces.

• Identified at least a dozen snipers, nearly one hundred enemies, and heavy weapons during the rooftop ambush 18.
• Located the sparse guard presence and underground layout of a weapons-processing facility 37.

Time Reversal

Saiki can restore a target to an earlier physical state.

• Reversed a Hydra assassin's body by ten minutes after the agent used poison, allowing Saiki to remove the poison before it killed him 14.
• Restored a heart-attack victim whose heart had stopped and whose brain had suffered severe damage 16.
• Cannot save someone who is already dead 14.

Mind Control

Saiki's Mind Control normally causes others to accept unnatural sights as natural.

• Failed upon his arrival in the Marvel world, causing civilians to panic at his appearance and head devices 5.
• Its failure helped Saiki recognize that the Summoning System had weakened him 5.

Other Psychic Abilities

Saiki is stated to possess a broad range of psychic powers beyond those demonstrated directly.

• X-ray vision 3
• Mind transmission 3
• Precognition 3
• Psychometry 3
• Petrification, concealed through his glasses 4

Equipment / Items

• Psychic-power suppressors — Antenna-like devices that restrain Saiki's overwhelming abilities and help him avoid causing disasters 8.
• Glasses — Used to conceal his petrification ability 4.
• Coffee pudding / coffee jelly — His favorite food and the incentive Shen He used to secure his acceptance of the summon 4 9 24.

Relationships

• Shen He — Master and summoner. Saiki initially resists the contract but agrees to assist Shen He in exchange for coffee jelly and the prospect of gaining finer control over his abilities. He protects Shen He while Shen He respects his refusal to kill 6 8 14 35.
• Phil Coulson — S.H.I.E.L.D. agent who investigates Saiki and Shen He after their public appearance. Saiki's surface-thought reading makes Coulson wary 7 9.
• Tony Stark — Saiki saves a dying patient during Tony's failed rescue attempt and later helps save Tony himself through time reversal. He dislikes Tony's flashy demeanor 16 17.
• Violet Evergarden — Fellow Servant. Saiki uses telekinesis to stop her from attacking Tony during her initial, weapon-like state 31.
• Shiki Ryougi — Fellow Servant. Saiki is present when Shen He uses the Virtual Reality Experience Helmet in an effort to reach her consciousness 47.
• Kokomi Teruhashi — Shen He suggests that Saiki may have romantic feelings for her, though Saiki insists love has nothing to do with him 23.
• Shun Kaidou — Saiki explicitly denies Shen He's joking suggestion that he is romantically interested in Kaidou 23.

Story Role / Major Arcs

Summoning and First Dungeon

Saiki becomes Shen He's first successful high-level Servant summon, though he initially refuses. After accepting, he struggles with his imposed Level 1 limitations and agrees to help Shen He clear dungeon instances in exchange for regular coffee jelly 3 6 9.

He removes his psychic suppressor during their first instance, easily restrains and defeats kobolds, and allows Shen He to practice with the Dominator pistol. His enjoyment of helping Shen He produces a rare smile 11. He later clears nearly half of an expanded dungeon hunting area and collects Enhancement Stones for his own advancement 13.

Hydra Conflict

Saiki prevents an ambulance attack intended to harm Shen He, captures the responsible Hydra agent, and reverses the agent's poisoning attempt 13 14. When the incident leaves a heart patient dying, Saiki returns in time to reverse the patient's condition completely 16.

He protects Shen He during a larger Hydra-linked rooftop assault, using Clairvoyance to assess the attackers. Though he dislikes Shen He's plan to reveal the Mirage mech and attract more attention, he agrees because their enemies have already targeted them 18 19.

Return Home and Continued Support

After the immediate conflict, Saiki chooses to return to his own world, taking Shen He's homemade coffee pudding with him. He remains contractually available to return whenever Shen He needs him 23 24.

He continues to aid Shen He during later summons, including helping open Violet's summoning sack, assisting in dungeon activities, and reconnoitering a weapons facility for Shen He and Natasha Romanoff 29 37.

Defensive Role

As Shen He's circumstances grow more violent, Saiki openly establishes his limit: he cannot bring himself to kill people and asks to serve defensively. Shen He accepts this conviction and remains grateful that Saiki continues to stand beside him 35.

Notable Quotes

“If I got serious, I had thirty-four ways to destroy all humanity in an instant.” 4

“I just don't want attention.” 6

“When killing your classmates or parents is as easy as moving a finger, killing becomes something truly terrifying. So please keep me in a defensive role whenever possible... Master.” 35

Trivia

• Saiki accepted a cross-world Servant summon because of premium coffee jelly after initially refusing outright 4.
• Shen He's homemade coffee pudding impresses Saiki more than a 2,950-yen coffee pudding 24.
• Saiki can return home without losing time there because he can travel back to the exact moment he disappeared 13.