Sword Art Online Wiki
Warning.png Spoiler Alert: This article or section contains details about plotlines not covered in the anime. Do not proceed unless you wish to be spoiled.
This article is missing some information.
You can help by adopting it and adding the missing information.
Missing Information: Alicization Arc chronology
This article is open for adoption.

Vassago Casals (ヴァサゴ・カザルス, Vasago Kazarusu?), known as PoH (プー, ?) in Sword Art Online (SAO) and Project Alicization, is a reoccurring character in the Aincrad Arc and the secondary antagonist of the War of the Underworld sub-arc of the Alicization Arc. As a member of a Korean crime syndicate, Vassago was ordered to log into Sword Art Online after it had become a death game, in order to indirectly assassinate a person already trapped in the game. Harbouring resentment against East Asians due to his troubled past, Vassago as PoH decided to instigate other players to kill each other and eventually founded «Laughing Coffin», the most infamous player-killing guild in the game. Eventually, PoH betrayed his own guild by disclosing the location of its hideout to the Clearers to facilitate a massacre between the two groups, while he himself avoided the clash. Vassago was one of the players logged out from the game on November 7, 2024, after which he returned to America and found employment with a private military contractor.

Vassago distinguished himself in virtual reality (VR) combat training against servicemen of the National Guard and Navy and was promoted to instructor. Eventually, Vassago received a contract to raid a mega-float in the Pacific Ocean in order to steal the Japan Self-Defense Force's (JSDF's) ground-breaking Bottom-Up Artificial Intelligence (AI), developed as part of Project Alicization. As the JSDF personnel managed to lock their main control room's systems before Vassago's team could reach it, Vassago and his boss, Gabriel Miller, decided to log into the virtual reality housing the Bottom-Up AI to retrieve the ideal AI individual from inside the virtual world, where the admin consoles were not locked down. As all advanced Human Empire accounts were affected by the lockdown, Vassago logged in with a Dark Knight account in the Dark Territory, planning to invade the Human Empire with the army of the Dark Territory to retrieve the individual they needed. At the end of the war, PoH was beaten by Kirito, who morphed his avatar into a cedar to prevent him from logging out. PoH was then forced to spend years in accelerated time in this state when his team members accidentally broke the Fluctlight Acceleration system, forcing it into its Maximum Acceleration phase. Although Vassago's body was eventually found in a seemingly-deceased state by his team, it mysteriously disappeared before it could be retrieved by the mercenaries during their withdrawal.


Sword Art Online

PoH as he appears in the anime.

PoH wore a dark, hooded poncho that covered him down to his knees, and wielded a Chinese kitchen knife-like dagger, called the «Mate Chopper».[4] Kirito recalls that PoH had an exotic, handsome appearance, as well as an enthusiastic, machine gun-like voice tone.[5] He had ample, black wavy hair[4] and a tattoo on the right side of his face.[6]


PoH is a cold and sadistic person who spread the idea that, as players would actually be killed by the mechanism of the NerveGear when a player's hit points reached 0, the designer of the mechanism, Kayaba Akihiko, would be the culprit of the murder, thus players had the right to kill other players and enjoy the game. This idea lured and brainwashed several orange players into going on a mad Player Killing craze and led to the first murders in the game.[4]

PoH is also a cool-headed man who rationally analyses the situation, like when he stopped the emotional Johnny Black to hear out Kirito before taking any action and ordered his men to retreat when he heard that Kirito had called for the help of thirty players from the clearers, as well as having drunk an antidote potion in advance and bringing many healing crystals with him.[4]


Vassago Casals was born in Tenderloin, a the slum district in San Francisco, to a mother of Spanish heritage.[7] Vassago's father was Japanese and had paid Vassago's mother for sexual services during his stay in the United States of America.[7][8] The affair resulted in an unexpected pregnancy and thus Vassago's mother desired to perform an abortion.[7] However, since his older son from his actual wife was born with a congenital kidney defect, Vassago's mother was forced to give birth, as his father hoped that the child could serve as a kidney donor.[7] As she despised the child she was forced to give birth to, Vassago's mother desired to name his son after the devil.[7] However, since the US birth certificate agency did not allow her to use obviously disparaging names, she chose to name him Vassago after a minor demon from Ars Goetia known as the «Prince of Hell».[7][9]

After Vassago's birth, his father only occasionally checked on his illegitimate son's health and only provided the bare minimum of child-rearing funding. At the age of fifteen, Vassago learnt about his father's plans to use him as a donor; however, since he did not have the choice to refuse his father's demands, Vassago agreed to donate his kidney under a single condition: the chance to move to Japan to start his life anew, as he would lose what little support he received from his father once he donated his kidney, while his prospects in America were non-existent. However, as Japan's legal procedures for international adoptions were too complicated and Vassago would not be able to receive a status of resident even if he were adopted, the boy had no choice but to turn to the criminal underworld.[7]

Hence, Vassago joined a Korean criminal syndicate, which provided him a counterfeit ID and trained him to become an assassin. By the age of twenty, Vassago had completed nine jobs for the syndicate. The tenth job assigned to him involved infiltrating Sword Art Online, a virtual reality that had trapped nearly ten thousand players in a death game just days prior. Vassago's objective was to kill a specific player from inside the game, as the target was too heavily guarded to kill in the real world and there was no guarantee that he would be killed by the death game he had become trapped in. As such, Vassago was ordered to become trapped in the death game and arrange the target's death in-game without directly attacking the player himself to avoid leaving evidence that it had been a planned assassination, being offered an astronomical sum of money in exchange for completing this obligatory task.[7]

Although nearly all unused NerveGears had been confiscated by the police by then, the syndicate managed to obtain one for Vassago, along with a copy of the game. Upon diving into the death game, Vassago chose to name his avatar PoH, an acronym of Prince of Hell, based on the name his mother had given him. Although PoH was obligated to kill a specific player by his syndicate, his contact with the Japanese players in the game reminded him of his father, making him realise that he loathed all East Asians due to his experience with his father. Hence, PoH began harbouring a desire to kill as many players in the game as he could, rather than just his intended target. He thus founded «Laughing Coffin», the largest player killer guild in the death game that was responsible for a great many player deaths.[7]


Aincrad Arc

Scherzo of Deep Night

Shortly after midnight on January 1, 2023, PoH ambushed Kirito in a castle in Karluin. Holding an allegedly paralysis-poison-coated knife at his back, PoH attempted to trick the boy into moving to the castle's non-Inner Area basement by bluffing that the castle's interior was located outside the safe zone as well. However, the man was forced to flee when Kirito escaped his clutches, covering his escape with a smoke bomb and swearing they would meet again.

A Murder Case in the Area

Hired by Grimlock to assassinate Schmitt, Caynz, and Yolko, PoH, along with Red-Eyed XaXa and Johnny Black, ambushed the three targets at the Hill of the Cross on April 23, 2024. Having confirmed that they had captured one of the leaders of the Divine Dragon Alliance, PoH considered how to derive amusement from their prey. When Johnny Black suggested forcing the three to kill each other for survival, PoH reminded him that they had killed the survivor the last time they played the game. However, the next instant PoH warned his companions as he heard a player, revealed to be Kirito, approaching them on a horse. Dismissing the solo player's comment on his attire, PoH restrained Johnny Black's sudden outburst and questioned the Black Swordsman's capability to handle the three of them alone. Informed that Kirito was prepared to stall them until thirty players from the clearers to arrive in ten minutes, PoH irritably cursed, before ordering his subordinates to withdraw. After warning Kirito that he would make him suffer one day, PoH departed the scene with his subordinates.

August, 2024

In August, 2024, PoH eventually grew tired of leading an excessively large organisation and decided to use it as a disposable pawn by intentionally leaking the location of its secret headquarters to the Clearers to orchestrate a massacre in the ensuing clash.[7]

The crusade would come to be known as the battle with the largest death count, as more than thirty players were killed during the fight. However, PoH was not found in the list of dead or captured people at the end of the battle.

After the crusade, PoH restored his cursor to green and remained active within the Inner Area.[10]

October, 2024

PoH in the crowd watching Kirito and Kuradeel's duel.

A couple of months later on October 18, 2024, PoH watched Kirito and Kuradeel's duel in Kamdet, the main settlement on the 74th Floor, and quietly left after the duel was over.[11] Sometime later, PoH heard that Kuradeel wished to kill Kirito, and thus recruited him into what remained of the Laughing Coffin, even teaching him how to make poisoned water that inflicted paralysis.[12]

Aftermath of Sword Art Online

The game was cleared just as PoH was about to aim for his greatest targets: Asuna and Kirito. Thus, Vassago's return to the real world only left him despondent and disappointed, rather than overjoyed. Since his syndicate boss was unwilling to fulfil his part of the deal by paying Vassago for his mission, the man killed the syndicate boss and took the money himself. As he would not be able to find another experience similar to Sword Art Online, Vassago decided to return to America and pursue the same experience by finding employment at the cyberoperations department of a private military contractor in San Diego. There, Vassago distinguished himself in VR combat training against servicemen of the National Guard and Navy and was promoted to instructor. However, Vassago remained unsatisfied with his stable life and instead desired an experience similar to Sword Art Online.[7]

Alicization Arc

Alicization Invading

This section is missing some information.
You can help by adopting it and adding the missing information.
This section is open for adoption.

On July 6, 2026, Vassago Casals accompanied Gabriel Miller, Critter, and nine other members of Glowgen Defense Systems' assault team during the attack on the Ocean Turtle. As the main control room's console had been locked before they managed to reach it, Vassago logged into Underworld as a dark knight, along with Gabriel as Vecta, in order to acquire Alice Zuberg's light cube via the World End Altar in Underworld.

Alicization Exploding

This section is missing some information.
You can help by adopting it and adding the missing information.
This section is open for adoption.

Alicization Awakening

This section is missing some information.
You can help by adopting it and adding the missing information.
This section is open for adoption.

Alicization Lasting

This section is missing some information.
You can help by adopting it and adding the missing information.
This section is open for adoption.

Non-canon Chronology

Hollow Fragment

NonCanonAlert.png Non Canon: Some or all events and details given in this section, may be considered non-canon to the main story.

During the events of Hollow Fragment, a Hollow version of PoH could be found in the Hollow Area. He bore the same mark as Kirito, making him a highly credible test player within the Hollow Area and allowing him to use the Administration Area. However, unlike the other AI data players within the Hollow Area, he was created by the collected data of the real PoH's emotional data, and his bloodlust and love of killing gave him a sense of knowledge as to what he was.

Hollow PoH was first seen while Kirito and Philia were traveling together in the «Bridge to Bastia» area. While spying on him and his own fellow Laughing Coffin members, PoH seemingly noticed Kirito and Philia watching nearby but acted like he was oblivious to them. After returning to the Administration Area afterwards, Philia was shocked when she found that PoH had entered the Administration Area himself, and proceeded to speak to her shortly after Kirito left to return to Aincrad. Assuming he was there to kill her, Philia guarded herself but he assured her he was not here to kill her, claiming that he simply wished to talk since they were both "orange" players. PoH tried to persuade her into turning on Kirito and joining him in Laughing Coffin, claiming that she would die if she continues to stay with Kirito.

As Kirito continued to try and help Philia remove her orange cursor, PoH returned and tried to once again convince her to help him. Since Philia continued to ignore PoH's influence, he claimed that they were mere data, rather than "humans", in the Hollow Area and also made a shocking declaration that if Kirito cleared the 100th floor and Aincrad was erased, the Hollow Area would be erased, along with them. PoH claimed that this was only possible because Kirito continued to come to the Hollow Area and, as a result, grew stronger. With this new fear and worry in Philia, PoH asked once more for help, claiming that he would not kill Kirito and all Philia had to do was lure him towards him. With that, he left once more, leaving Philia in disarray.

PoH's words got through to Philia, as she unknowingly aided him in trapping Kirito in a dungeon where warp crystals and messages could not be used, making it a perfect place for PoH killing his victims, since it was full of powerful monsters. After seemingly sending Kirito to his death, PoH went on to execute his plans to use the Hollow Area's main console to start a massive transfer of data from the Hollow Area to Aincrad, which would overwrite the data of all the players with their Hollow data, essentially making the system treat the AI data as the players.

Deep within the previously sealed off area within the Hollow Area, PoH revealed his true motives to Philia, breaking her down to tears that he tricked her into sending Kirito to his death. With him out of the way, PoH would have no one stopping him from enjoying his concept of paradise - slaughtering the other AI data players within the Hollow Area with no end. Seeing no further use for her as she turned on him, PoH proceeded to torture and abuse Philia before deciding to end her life by cutting her head off with his Chopper. But before he could, Kirito suddenly appeared and sliced off his hand, freeing Philia. A battle ensued between Kirito and PoH, with Kirito the victor and the virtual data that was PoH deleted. However, though he was defeated, Kirito and his friends still had to stop the massive transfer PoH had set in motion to prevent the re-writing of Aincrad.


Project Alicization

Stat Value Time
Unit ID DCH20461[13] Permanent
Durability 3714[13] Dark Knight account default value
Object Control Authority 70[13] Dark Knight account default value
System Control Authority 30[13] Dark Knight account default value

Known Equipment

Sword Art Online

Name Type Acquisition Notes
«Mate Chopper» Large Dagger Boss drop


  • PoH likes saying the English catchphrase, «It's showtime».[14]
  • PoH is a multilingual player who is well versed in at least three languages: English, Japanese, and Spanish.[5]
  • Vassago, also known as the Prince of Hell, is one of the seventy-two demons recorded in Goetia, a grimoire from medieval times.[15] PoH stands for "Prince of Hell".[citation needed]


See: Vassago Casals/Image Gallery



Major Characters
Alice Zuberg - Asada Shino (Sinon) - Ayano Keiko (Silica) - Eugeo - Kayaba Akihiko - Kikuoka Seijirou - Kirigaya Kazuto (Kirito) - Kirigaya Suguha (Leafa) - Shinozaki Rika (Lisbeth) - Tsuboi Ryoutarou (Klein) - Yui - Yuuki Asuna (Asuna)
SAO Players
Aincrad Liberation Force/ALS Hokkaiikura - Joe - Kibaou - Kobatz - Liten - Melonmask - Okotan - Schinkenspeck - Thinker - Yulier - Yakumo
Divine Dragon Alliance/DKB Buxum - Hafner - Lind - Morte - Schmitt - Shivata - Yamata
Fuumaningun Isuke - Kotaru
Fuurinkazan Dale - Dynamm - Harry One - Issin - Klein - Kunimttz
Golden Apple Caynz - Grimlock - Griselda - Schmitt - Yolko
Knights of the Blood Asuna - Daizen - Godfree - Heathcliff - Kirito - Kuradeel - Nautilus
Laughing Coffin Johnny Black - Kuradeel - Kuro - PoH - XaXa
Legend Braves Beowulf - Cu Chulainn - Enkidu - Gilgamesh - Nezha - Orlando
Moonlit Black Cats Ducker - Keita - Kirito - Sachi - Sasamaru - Tetsuo
Titan's Hand Rosalia
Two-Handed Builders Agil - Lowbacca - Naijan - Wolfgang
Others Argo - Ashley - Ceba - Coper - Diavel - Gin - Gwen - Kein - Lisbeth - Lux - Mina - Nishida - Rossa - Ryufior - Sasha - Silica - Yuna
Beta Testers Argo - Coper - Diavel - Isuke - Kotaru - Morte - Kirito
NPC Angel - Kizmel - Leyshren Zed Yofilis - Lion - Myia - NPC Orchestra - Pina - Ruru - Scarecrow - Theano - Tilnel - Tin - Toto - Yui
Non-Canon Aaaa - Alberich - Leafa - Philia - Rain - Sinon - Strea - Yuuki
ALO Players
Cait Sith Adie - Alicia Rue - Silica - Sinon
Gnome Agil - Tecchi
Imp Yuuki
Leprechaun Ceba - Granze - Lisbeth - Talken
Pooka Sasha
Salamander Eugene - fastuosa - Gtacs - Jun - Kagemune - Klein - Mortimer - UxperXJ
Spriggan Kirito - Kuro - Nori
Sylph Erika - Fukaziroh - Leafa - Lux - Recon - Sakuya - Sigurd
Undine Asuna - Chrysheight - Siune - Thinker - Yulier
NPC/Navigation Pixie Angel - Emely - Hraesvelg - Leviathan - Nerakk - NPC Orchestra - Pina - Skuld - Thiazi - Thor - Thrym - Tonky - Urðr - Verðandi - Yui
Others/Unknown Ashley - Fairy King Oberon - Garnet - Gwen - Marinca - Saitou Shouichi - Slug Researchers
Non-Canon Alice Zuberg - Argo - Black Lotus - Eugeo - Heathcliff - Persona Vabel - Philia - Rain - Sachi - Seven - Strea - Sumeragi - Yuna
GGO Players
Dyne's Squadron Arashi - Dyne - Ginrou - Jin - Miso - Sinon
BoB Participants Blackwood - Colonel Liberty - DA*LU - Dyne - E.J. - Fernil - Garrett - huuka - Jack Reacher - JIGEN - Kakouton - kaeeeede - Kakameposu the II - Keith - Kirito - Lion King Richie - Masaya - Musketeer X - No-No - Pale Rider - Pancho - Raiden - Licoco - Setsugekka - Shishigane - Sinon - Sterben - Stinger - Subtilizer - Ten-Q - Uemaru - Usujio Tarako - Yamikaze - XeXeeD - XYZ
Death Gun Victims Garrett - Pale Rider - Usujio Tarako - XeXeeD
Squad Jam Participants KKHC Shirley
LPFM Fukaziroh - LLENN - M - Pitohui
MMTM Bold - David - Jake - Kenta - Lax - Summon
Narrow Dashin - Hidehide - Nagama - Nobu - Saika - Yasu
SHINC Anna - Eva - Rosa - Sophie - Tanya - Tohma
ZAT Benjamin - Casa - Frost - Koenig - Yamada - Let's Play Host
ZEMAL Heuy - Max - Peter - Shinohara - Tomtom
Others Clarence
Other main series characters Behemoth - Spiegel
AGGO manga original characters Batian - Boss - Costa - Lorosae - Panama - Rio
Underworld Resident
Human Empire Rulid Village Algu - Alice Zuberg - Bercouli - Donetti - Doyke - Eugeo - Garitta - Gasupht Zuberg - Ivenda - Jaina - Jink - Kirito - Nigel Balbossa - Orick - Ridack - Sadina Zuberg - Selka Zuberg - Sister Azalia - Sulinea
Zakkaria Banou Wolde - Egome Zakkarite - Kelgam Zakkarite - Telin Wolde - Telulu Wolde - Toriza Wolde
Centoria Azurica - Cardinal - Quinella - Sadore
Sword Mastery Academy Azurica - Eugeo - Frenica Szeski - Golgorosso Balto - Humbert Zizek - Kirito - Raios Antinous - Ronye Arabel - Sortiliena Serlut - Tiese Shtolienen - Volo Levantein - Zobun
Central Cathedral Cardinal - Charlotte - Chudelkin - Elevating Operator - Fizel - Linel - Quinella
Integrity Knight Alice Zuberg - Bercouli - Dakira - Deusolbert - Eldrie Woolsburg - Eugeo - Fanatio - Fizel - Giro - Hobren - Jeis - Linel - Renly - Scheta
Dragons Amayori - Himawari - Hinageshi - Hoshigami - Kazenui - Shimosaki - Takiguri - Tsukigake - Yoiyobi
Others Almera Woolsburg - Eschdol Woolsburg
Dark Territory Black Iums D.I.L - Dampe - Fu Za - Iskahn - Lengil Gira Scobo - Lipia Zancale - Vixur Ul Shasta - Yotte
Orcs - Renju - Rilpirin
Ogres Furgr
Giants Sigurosig
Goblins Aburi - Hagashi - Kosogi - Kubiri - Oroi - Shibori - Ugachi
Underworld Visitors
Agil - Alicia Rue - Asuna - Eiji - Eugene - Gabriel Miller - Hirono Takashi - Jun - Kirito - Klein - Leafa - Lisbeth - Moonphase - Nori - Sakuya - Silica - Sinon - Siune - Tecchi - Vassago - YUNA
Asuka Empire
Players Clevel - Koyomi - Merida - Nayuta - Ran - Yanagi - Yuuki
NPC Clovis (AI)
Staff Torao
Reality/Other Games
Rath Aki Natsuki - Higa Takeru - Hiraki - Ichiemom - Kikuoka Seijirou - Koujiro Rinko - Nakanishi - Niemom - Yanai
Others Alicia Klingerman - Cel - Clovis - Critter - Doctor Kurahashi - Eiji - Endou - Fujita Shin - Kirigaya Midori - Okano Kouji - Oosawa Mizue - Oosawa Sachie - Sada Akiyo - Satou Rei - Shigemura Tetsuhiro - Yuna - Yuuki Kouichirou - Yuuki Kyouko - Yuuki Shouzou
Non-Canon Gattas - Genesis - Laraiah - Premiere - Richter - Sigil - Tia