|Voice Actor(s)||Takanori Hoshino|
|Affiliation|| Spirits and Such Consultation Office |
Ultimate 5 (former)
Serizawa is slightly taller than Reigen in most depictions, although sometimes is the same height. Whilst still a member of Claw, he had curly black hair, somewhat heavy eyebrows, a thin mustache, and stubble. He wore an orange robe over a black shirt, along with black pants, and bright green crocs. He carried his white umbrella with him at all times. After the fall of Claw, he no longer carries his umbrella casually.
After being invited to work with Reigen and Shigeo at the agency, Reigen trims Serizawa's hair and shaves his face. When working at the agency he wears a blue two-piece business suit.
Serizawa was a very sheltered and naive person prior to leaving Claw. He still retains some of these attributes. He placed all his trust in Toichiro Suzuki and looked up to him as a personal savior, and followed his orders without question. Before beginning his work at the Spirits and Such Consultation Office, if he was separated from his umbrella he would panic and completely lose control of his psychic power, which would cause heavy damage to his surroundings. He was haunted by a deep fear of his own power.
Serizawa is a very nervous person. Due to his years under Toichiro Suzuki, he seems to have difficulty acting on his own without guidance from others. However, after the fall of Claw, joining Reigen's agency and starting to attend night school, Serizawa begins coming out of his shell and becoming more independent.
Serizawa, before and during his time with the Spirits and Such Consultation Office, is shown to be caring of others' wellbeing, even going as far as keeping himself in his room for the sake of others' safety. Currently, he is more careful with his feelings and considers his thoughts more before giving advice or commentary. He's gained a little more confidence by working alongside Reigen and making friends with the people in his classes.
By the time of the REIGEN spinoff, he seems to be competent and quite confident, showing off his powers for Tome and even lecturing her on her obsession with becoming a psychic.
At age 12, Serizawa became so overwhelmed by fear of his own psychic powers that he refused to leave his bedroom in fear of hurting others. Lacking guidance from an adult understanding his problem and seemingly not helped by the non-esper counselors his mother had hired, he remained in his bedroom for 15 years until Toichiro Suzuki finally coaxed him to leave (and by doing so, join Claw) by offering him an umbrella and encouraging him to view it as an extension of his room. Serizawa followed him, hoping to learn to control his powers and rejoin society. Instead, Suzuki used him to further the aims of Claw, leaving him and his well-being utterly dependent on both Suzuki and his umbrella. Serizawa convinced himself that Claw was a company, that Suzuki was its president, and that he himself was an employee.
World Domination Arc
When Joseph reveals his status as a double agent to Suzuki, Serizawa appears and lectures him about how lying isn't a very nice thing to do. Joseph tries to restrain him with his smoke but he breaks free and uses his powers to blast him out the window.
When Mob is climbing the stairs to confront Suzuki, he encounters Serizawa and tells him bluntly that he was being used. When he tried to argue in his own defense, Mob told him that he was following the wrong person. He made a token attempt to fight Mob, using his umbrella as both a weapon and a shield, but was eventually won over by the sincerity and empathy of Mob's 100% Friendship. By sharing his energy with Serizawa, Mob was also able to share his memories of true friendship with him, which helped Serizawa to understand the true nature of his relationship with Suzuki.
He later used his umbrella to save Reigen from Suzuki's wrath. Suzuki retaliated by blasting Serizawa with psychic energy until his umbrella was torn to shreds, then draining Serizawa's power to use for himself.
Serizawa is present at Toichiro's arrest. His former boss then tells him that he never really cared about him.
Divine Tree Arc
Serizawa decides to accept Reigen's offer and he start to work at Spirits and Such Consultation Office. At first Reigen decides to cut his hair and shave his beard.
He and Mob exorcize Yokai drawn to the Divine Tree.
Telepathy Club Mini-Arc
Reigen invites Serizawa to the New Year's Eve meeting, but he already has plans with friends from school.
When ???% destroys the city, Serizawa and Reigen go check out what is happening. Serizawa's power is sapped by Mob's tornado, and at the request of Reigen, he retreats.
He takes part and invites Sho to Reigen's birthday party.
Powers & Abilities
When he was a member of Claw, Toichiro Suzuki stated that Serizawa is the most powerful of the Ultimate 5. He is strong enough to block an attack from Suzuki at 3% of his power output as well as to put up a fight against Mob. His psychic aura takes on a purple color with a TV static pattern within.
Serizawa possesses extremely powerful psychokinesis, which he channels through his umbrella to make it a powerful weapon both in melee and ranged combat. He can open it to use it as a shield or close it to use it as a powerful bludgeon. He also demonstrated an unnamed technique where he charged a destructive energy ball at the tip of the umbrella and launched it at the opponent. He used the umbrella as a conduit in order to not lose control of his immense power, though he has recently overcome this issue and doesn't require the umbrella to control himself anymore.
- (To Mob) "Please... don't make me angry. Do you know how much your words hurt?"
- "Ability... I can build... plastic models really well. Ah... What else..."
- "How awesome is that... I talked to the prime minister." 
Notes & Trivia
- By the time he begins working at Spirits & Such, Serizawa lives alone. 
- Serizawa is reluctant to try spicy foods. 
- He regularly consumes cup noodles. 
- He is shown to be very fond of children - he is friendly toward Sho, the only esper who doesn't want to fight Mob (because he is a middle schooler), and protective of Tome in the REIGEN spinoff manga.
- Serizawa has not told his mother about his terrorist past - she is unaware of what Claw is as well. 
- He considers Reigen to be a respectable person. 
- He is described as being honest and sincere, but too estranged from the world. 
- ↑ Mob Psycho 100 Manga — Vol. 11 Chapter 89 (page 5). He mentions it was three years since Toichiro found him and he was 27 at the time.
- ↑ OnePunch-Man Manga; Chapter 81, page 5
- ↑ OnePunch-Man Manga; Chapter 90, page 50
- ↑ OnePunch-Man Manga; Chapter 89, page 29-32
- ↑ OnePunch-Man Manga; Chapter 89
- ↑ OnePunch-Man Manga; Chapter 89
- ↑ 7.0 7.1 7.2 Mob Psycho 100 || OVA Drama CD - Episode 1 - Serizawa's Preparation
- ↑ Mob Psycho 100 || OVA Drama CD - Episode 2 - Going Shopping
- ↑ Mob Psycho 100 || OVA Drama CD - Episode 7 - Breakfast
- ↑ Otomedia May 2019 - Serizawa Katsuya
|Mob Psycho 100 Characters|
|Main Protagonists||Shigeo "Mob" Kageyama • Arataka Reigen • Dimple • Ritsu Kageyama • Teruki Hanazawa • Sho Suzuki|
|Side Characters|| Salt Middle School
Takane Tsubomi • Tome Kurata • Haruto Kijibayashi • Mameta Inukawa • Shirihiko Saruta • Momozo Takenaka • Musashi Goda • Hideki Yamamura • Hiroshi Kumagawa • Jun Sagawa • Ryohei Shimura • Tenga Onigawara • Ichi Mezato • Emi • Shinji Kamuro • Hikaru Tokugawa
|Claw|| Boss & Ultimate 5
7th Division Scars
|Evil Spirits & Entities||Keiji Mogami • Psycho Helmet • The Dragger • Wriggle Wriggle • Scent-Ghoul • Boss • Ceiling Crasher • ???%|