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Real Name: Sydney Green

Identity/Class: Human mutant

Occupation: Student

Group Membership: None; formerly Chevaliers (Bling!/Roxy Washington, Flubber/Nick Shelley, Foxx/Raven Darkholme, Rain Boy/Carl Aalston)

Affiliations: Ariel, Eye-Boy (Trevor Hawkins), the Five (Egg/Fabio Medina, Elixir/Joshua Foley, Proteus/Kevin MacTaggert, Hope Summers, Tempus/Eva Bell), Strong Guy (Guido Carosella), X-Men (either faculty members from Xavier's School for Gifted Youngsters or other X-Men teams) (Angel/Warren Worthington III, Beast/Hank McCoy, Cannonball/Sam Guthrie, Colossus/Piotr Rasputin, Cyclops/Scott Summers, Danger, Dazzler/Alison Blaire, Emma Frost, Gambit/Remy LeBeau, Havok/Alex Summers, Iceman/Robert Drake, Nightcrawler/Kurt Wagner, Northstar/Jean-Paul Beaubier, Polaris/Lorna Dane, Psylocke/Betsy Braddock, Rogue/Anna Marie, Shadowcat/Kitty Pryde, Storm/Ororo Munroe, Wolverine/James "Logan" Howlett), X-Men students (Xavier Institute for Higher Learning, Graymalkin Industries and Utopia) (Anole/Victor Borkowski, Armor/Hisako Ichiki, Blindfold/Ruth Aldine, Cipher/Alisa Tager, Dust/Sooraya Qadir, Elixir/Josh Foley, Ernst, Gentle/Nezhno Abidemi, Glob Herman/Robert Herman, Graymalkin/Jonas Graymalkin, Hellion/Jullian Keller, Indra/Paras Gavaskar, Ink/Eric Gitter, Loa/Alani Ryan, Match/Ben Hamill, Mercury/Cessily Kincaid, No-Girl/Martha Johannson, Pixie/Megan Gwynn, Prodigy/David Alleyne, Quill/Maxwell Jordan, Rockslide/Santo Vacarro, Surge/Noriko Ashida, Three-In-One/Celeste, Mindee, Phoebe Cuckoo, Trance/Hope Abbott, Wallflower/Laurie Collins, Wolf Cub/Nicholas Gleason, X-23/Laura Kinney)

Enemies: Avengers (Norman Osborn's team), Belasco, H.A.M.M.E.R., Mystique (Raven Darkholme), Norman Osborn, Purifiers, Mimic (Calvin Rankin), Selene's Inner Circle (Eli Bard, Blink/Clarice Ferguson, Mortis/Lois London, Senyaka, Wither/Kevin Ford), William Stryker, S'ym

Known Relatives: None

Aliases: "Randy" called by Bling!

Base of Operations: Krakoa, most likely the Sextant, Akademos Habitat;
     formerly Utopia, coast of San Francisco Bay, California;
     formerly Graymalkin Industries, Marin Highlands, San Francisco, California;
     formerly Xavier Institute for Higher Learning, Salem Center, New York;
     formerly New Jersey (possible Place of Birth)

First Appearance: X-Men II#171 (August, 2005)

Powers/Abilities: Onyxx had superhuman strength (lifting 5 tons), and a hide comprised of an organic rock substance that granted him enhanced durability. For some reason, Onyxx insisted on covering his head with a metal helmet of unknown composition. Onyxx had four eyes that glowed permanently as well as an inhuman looking skeleton.

Height: 6'11"
Weight: 375 lbs.
Eyes: Red
Hair: None


(X-Men: The 198 Files - BTS) - Sidney Green was a boorish, clumsy child, growing up in the New Jersey foster care system, often the target of cruel bullying by children and adults alike. This was in part caused by the fact he was an inveterate bed-wetter, giving him the funk of uncleanliness, which further ostracized him and made him miserable. Green's attempts to curb his nightly emissions by avoiding liquids led to dizziness and dehydration. Once his mutant abilities kicked in, a blissful drought beneath the waist set in, and there was a lack of sodden sheets.

(X-Men II#171 - BTS) - After his mutation manifested itself, Sidney applied and was admitted to the Xavier Institute. He was among the students selected to join one of the special training squads mentored by members of the X-Men. He was placed on the Chevaliers, which was led by Gambit.

(X-Men II#171) - Onyxx participated in a Chevaliers training session in the Danger Room where they had to attack their tutor Gambit. The battle was stopped midway by Emma Frost who had come to introduce the Chevaliers' newest member Foxx (who turned out to be Mystique in disguise). The students were stunned by Foxx who immediately began to make overt sexual avances towards Gambit, asking him for "one-on-one sessions". During their lunch break Onyxx played a game of baseball with Bling! and Flubber when they noticed Rogue giving Foxx the brush off. Onyxx took the opportunity to talk to Foxx and asked if the two of them could have a little "fun" together sometime. Unimpressed Foxx replied the only fun they might have is if she would tear of his ridiculous face and remove his hands before leaving him with a stump. Onyxx, however, didn't get the hint and became quite smitten with Foxx. Later that night Onyxx alongside Flubber and Foxx participated in another training exercise with Gambit in the Danger Room.

(X-Men II#172) - Gambit took his Chevaliers on a field trip as an excuse to get away from Rogue to do some thinking about their relationship. Taking a break at a refreshing spring, Onyxx and the others noticed how Foxx once again tried to seduce Gambit which led Bling! to comment she could throw up looking at the scene. Onyxx, however, was getting more upset by the minute since he really liked Foxx but was turned down every time. Later that night Onyxx, Flubber and Rain Boy decided to confront Gambit about his untoward behavior towards Foxx, unable to control himself Onyxx attacked Gambit only to be knocked down on the rocks with his face, breaking part of his mask. Gambit was less than pleased that his students thought he would ever seduce a student and when Foxx suddenly appeared from the shadows (fresh from a fight with Bling!) Gambit explained he found it "magnifique" they would support each other. Gambit continued that if they would disappear from his sight in ten seconds he would forget their "mutiny", somewhat scared the students returned to their camp. The next morning the Chevaliers returned to Xavier's. Later that day, Gambit decided it would be for the best if Foxx was moved to another squad. When he went to tell her the news, Mystique revealed her true identity.

(X-Men II#173) - Onyxx and the Chevaliers were left in the dark about Mystique and her plan to join the X-Men. They were too busy enjoying some hamburgers and soda, while discussing the question if Gambit had cheated on Rogue or not. And while Bling! wondered where Foxx could be, Rain Boy was already over the subject and asked who would win in a fight, Wolverine or Beast.

(X-Men II#174) - The next morning Onyxx and the Chevaliers witnessed the arrival of several senior X-Men members who had come to decide whether Mystique could join the team. Onyxx wondered if they'd come to punish them because of their little rebellion against Gambit but having learned Foxx's true identity Bling! explained what was really going on. Onyxx refused to believe "his" Foxx had been a fake, the idea alone drove him into a mad rage which took all of his friends to calm him down. However, still upset and confused Onyxx decided to confront Mystique in her prison. Upon arriving in her cell it became painfully obvious he thought Mystique was truly Foxx and even attacked her. As Onyxx grabbed Mystique by the throat he yelled to turn back into Foxx and proclaim her love for him. Mystique managed to break free and hit Onyxx in the head with a toilet after which he was taken into the medic bay. Before he received his anesthetic, he signed a legal waiver admitting culpability in his disagreement with Mystique. In the end Mystique chose to leave Xavier's on her own will.

(X-Men: The 198 Files - BTS) - Within days, Onyxx was able to walk again. Yet, the experience of being smashed in the head with a flush-lavatory triggered unfortunate memories of his childhood, perhaps permanently traumatizing him.

(House of M#8 - BTS) - The Scarlet Witch caused millions of mutants to lose their powers by casting a reality altering spell. The event, known as M-Day, reduced the number of gene active mutants to a mere 300 worldwide. Onyxx was one of the select who kept his mutant powers.

(New X-Men II#23) - Two weeks after the global depowering that had become known as M-Day all student training squads disbanded since only twenty-five X-Students had retained their powers. Xavier Institute headmaster Emma Frost pitted all remaining students against each other in a battle royale to choose a team who would go on to train as New X-Men. Onyxx was stoked he would be allowed to fight the other students and bumped fists with Rockslide who thought it was the best day of his life. During the fight Onyxx set his sights on X-23 but was unable to hit her when Hellion rescued her. After the battle was finished seven students were chosen to train as X-Men, none of the former Chevaliers were chosen. Not much later, Xavier Institute headmasters Cyclops and Emma Frost decided all depowered students should return home for their own safety. A first busload of students had already left when a second, carrying another 42 former mutant teens, was blown up. The attack was carried out by the Purifiers who were acting on the orders from their leader, the Reverend William Stryker.

(New X-Men II#24) - Onyxx was present during the funeral of the deceased students, even in death fourteen of the forty-two deceased students were unwelcome to return home and were buried at Xavier's cemetery.

(X-Men: The 198 Files - BTS) - General Demetrius Lazer of O∗N∗E made a threat assessment of the remaining mutants. In this report, he analyzed Onyxx and assessed his threat level as significant.

(New X-Men II#27) - Sometime later the Purifiers managed to infiltrate the Xavier Institute in the hopes of killing all remaining mutants. During their all out attack, Emma Frost telepathically warned all students to remain in their rooms. Ignoring Frost's warning Onyxx wandered through the hallways and was attacked by William Stryker himself who used a part of the Nimrod sentinel to attack him. As Onyxx fell to the ground Stryker prepared to finish the boy off but was stopped just in time by Frost and the New X-Men. After Stryker's defeat, the corpse of fellow student Quill was found and taken in by the agents of O∗N∗E.

(New X-Men II#32) - Onyxx was present amongst other students, the X-Men and their allies during a memorial service in honor of all who had fallen in the X-Men's long struggle in achieving Xavier's dream of peaceful co-existence.

(New X-Men II#35) - Having heard how heroic Bling! had been during Apocalypse's attack Prodigy of the New X-Men offered her a place on the team. Onyxx was present when Bling! declined the offer, opinionated as ever Bling! declined feeling anybody wanting to join the X-Men would have a serious death wish. She continued that she and Onyxx were thinking about leaving Xavier's before Sentinel Squad O∗N∗E would change their minds and execute the remaining mutants. Seconds later Colossus came into the room to tell the students presence was requested by O∗N∗E in the assembly hall, prompting Bling! to repeat her line about a potential firing squad.

(New X-Men II#37 - BTS) - Onyxx was abducted to Otherplace (limbo) by the demon-lord Belasco along with all the other students. Belasco had sensed his former apprentice Illyana Rasputin was alive again and figured that taking the X-students prisoner was a first step to retrieve her.

(New X-Men II#38) - Onyxx was fitted with giant, binding shackles and was forced to watch helplessly as Belasco tortured Prodigy, even ripping out his heart.

(New X-Men II#41 - BTS) - After a fierce and ferocious fight, Illyana Rasputin with the help of several New X-Men reclaimed her control over Otherplace, sending all the students home.

(Uncanny X-Men I#500 - BTS) - After the destruction of the Xavier Institute, Onyxx and the other students moved to Graymalkin Industries in San Francisco, the new home of the X-Men.

(X-Men: Manifest Destiny#3/3) - Onyxx and Indra participated in a training session with Colossus in the Danger Room.

(Dark Avengers/Uncanny X-Men: Utopia#1) - When the Humanity Now! Coalition marched on San Francisco, they were quickly met by anti-Proposition X protestors. As violence and riots erupted Cyclops dispatched his X-Men to restore order. Later that day Onyxx and the X-Men watched a news report about the situation. Later that night Norman Osborn (head of the national peacekeeping organization H.A.M.M.E.R.) publicly branded Cyclops an instigator and deployed his Avengers to quell the conflict and arrest anyone who stood in their way. That night Onyxx joined Loa and Mercury to stop the fights on Telegraph Hill but after all the people left for City Hall the students decided to stay behind until Cyclops checked up on them several hours later. Cyclops then took Onyxx and the other students with him to City Hall where Greek war God Ares of Osborn's Avengers arrived.

(Uncanny X-Men I#513) - The next morning Onyxx and the students witnessed news reports of an all-new, all-different X-Men team under leadership of Emma Frost, now calling herself the Black Queen.

(Dark Avengers I#8) - Onyxx was present when Pixie arrived to reveal Cyclops had given the order to attack Osborn's forces.

(X-Men Legacy I#226) - Cyclops had teamed up Onyxx and old X-Men associate teleporter Ariel to retrieve any casualties in the ongoing war between the X-Men and Osborn's regime. When the Stepford Cuckoos alerted them to another fallen casualty Onyxx and Ariel arrived at 20th and Mission to find the unconscious Trance.

(X-Men Legacy I#227) - Onyxx gently grabbed Trance while Ariel opened another teleportation door back to the X-Men's HQ. However when they arrived Trance had disappeared. Ariel was quick to reason it might've been because of her ghost-like powers.

(Dark Avengers/Uncanny X-Men: Exodus) - The final showdown between the X-Men and Osborn's Avengers took place on Utopia, the former Asteroid M that floated in the waters around San Francisco. Onyxx helped his fellow students to attack Mimic of Osborn's X-Men. After defeating Osborn's Avengers and X-Men the real X-Men decided to leave San Francisco and moved to their own nation called Utopia.

(X-Men Legacy Annual I#1/1) - When the X-Men had become aware of Emplate's presence on Utopia, they gathered all mutants present to warn them of the predatory mutant. Cyclops ordered everyone to stick together, because on their own they'd be easy prey for Emplate. Unbeknownst to the X-Men, Emplate had come to look for Penance who he'd previously fed on and whose diamond form could last indefinitely. When he realized Penance was no longer with the X-Men, he settled for the next best thing: Bling!. Having listened to Cyclops, she stuck together with Onyxx, Rockslide and Hellion but when the boys started to bicker amongst themselves again, Roxy took a break from "all of the testosterone". Promising to stay in sight, Bling! nevertheless wandered off and was eventually abducted by Emplate.

(X-Men Legacy I#228) - Onyxx, Hellion and Rockslide quickly made their way to Cyclops to tell of Bling!'s abduction. But when Trance (Hope Abbott) was the only mutant who could see Emplate's floating lighthouse base, it was decided Rogue would borrow her powers to rescue Bling!.

(X-Men Legacy I#230) - Onyxx was present when Rogue returned from her mission and Hope awoke. Rogue's plan had been successful as several moments later Emplate's firehouse arrived and crashed on Utopia. After Bling! unleashed a powerful attack against Emplate the X-Men took it over from there. Now Bling! had been saved everyone returned to their usual business.

(Nation X#2/1) - Onyxx was enjoying some time in the lounge when Northstar showed up to introduce his boyfriend Kyle Jinadu. In a snarky tone Hellion called him Northstar's "normal".

(Nation X: X-Factor#1) - Rockslide, Armor and Onyxx were playing a game of football on the outskirts of Utopia when they were suddenly interrupted by Strong Guy of the visiting X-Factor Investigations. Strong Guy took the ball from Rockslide and pushed him over, after which he sat down on him. Armor and Onyxx couldn't help but laugh at seeing the proverbial irresistible force meeting the immovable object. Enraged, Rockslide threw Strong Guy up into the air, which led to a friendly tug of war that Armor and Onyxx soon tired of. They left the two combatants to fend for themselves.

(X-Force III#23) - In a quest to become a true goddess Selene sent her Inner Circle into the midst of the besieged and battle-weary X-Men to retrieve the mystical spirit blade, a sacred knife vital in her ascent to godhood. Onyxx involved himself in the fight against Selene's Inner Circle, attacking his former fellow student Wither, who used his death touch on him. Within moments, Sidney was reduced to a pile of ashes. After the fight, which ended with the Inner Circle obtaining the blade, Dust mourned Onyxx's death. She picked up his metal mask, the only thing that was left of Onyxx.


(Phoenix Resurrection: The Return of Jean Grey#4 - BTS) - When the Phoenix Force returned to Earth to once again try and merge with Jean Grey, it trapped her in an imaginary world where the Phoenix Force had created several constructs of deceased X-Men, amongst them Onyxx. Dressed in red X-Men costumes the constructs fought the real X-Men until a small squad successfully reached Jean upon which the constructs disappeared.

(X-Factor IV#5 - BTS) - Following the Krakoan resurrection protocols, Onyxx was among the many mutants resurrected by the Five (Egg, Elixir, Proteus, Hope Summers and Tempus). Onyxx was one of the many who accepted the invitation to remain on the sovereign mutant island nation, ruled by the Quiet Council.

(X-Factor IV#5) - Learning former X-Men student Wind Dancer (Sofia Mantega) had been resurrected, Onyxx and other former students met up at the Boneyard to celebrate.

Comments: Created by Peter Milligan (writer), Salvador Larroca (pencils), Danny Miki, Allen Martinez (inkers).

The fact Onyxx's metal mask survived Wither's touch indirectly proves it wasn't part of his body or made of organic steel.

During an interview with Comic Book Resources New X-Men writers Kyle & Yost revealed they'd initially wanted to kill the character:
Is there any character who you wanted to kill, but the X-office wouldn't let you?
Yost: You know, they stopped us from killing Onyxx back in "New X-Men," but we finally got him in "X-Force."
Kyle: That's true!
Yost: I hated that character. No offense to Peter Milligan, who I think is great, but I was not a fan. But we never do anything maliciously - it's all within the story...

Onyxx received profiles in X-Men: The 198 Files and X-Men: Earth's Mutant Heroes, he was also part of the New X-Men profile in X-Men: Messiah Complex - Mutant Files.

Profile by MarvellousLuke

Onyxx has no known connections to

images: (without ads)
X-Men: Earth's Mutant Heroes, Onyxx's entry (main image)
X-Men II#174, p22, pan2 (x-ray of skeleton)
X-Men II#171, p19, pan1 (training with Gambit)
X-Men II#174, p19, pan2 (hit in the head with a toilet)
New X-Men II#27, p17, pan6 (attacked by Stryker)
X-Men Legacy I#226, p8, pan5 (with Ariel)
X-Force III#23, p15, pan3,4 (death)

X-Men II#171 (August, 2005) - Peter Milligan (writer), Salvador Larroca (pencils), Danny Miki, Allen Martinez (inkers), Mike Marts (editor)
X-Men II#172 (August, 2005) - Peter Milligan (writer), Salvador Larroca (pencils), Danny Miki, Allen Martinez (inkers), Mike Marts (editor)
X-Men II#173 (September, 2005) - Peter Milligan (writer), Salvador Larroca (pencils), Danny Miki, Allen Martinez (inkers), Mike Marts (editor)
X-Men II#174 (October, 2005) - Peter Milligan (writer), Salvador Larroca (pencils), Danny Miki, Allen Martinez (inkers), Mike Marts (editor)
X-Men: The 198 Files (January, 2006) - Eric J. Moreels, Marc-Olivier Frisch, Brian E. Wilkinson (writers), Jeff Youngquist (editor)
New X-Men II#23 (April, 2006) - Craig Kyle, Chris Yost (writers), Mark Brooks, Paul Pelletier (pencillers), Jaime Mendoza (inks), Mike Marts (editor)
New X-Men II#24 (May, 2006) - Craig Kyle, Chris Yost (writers), Paco Medina (pencils), Juan Vlasco (inks), Mike Marts (editor)
New X-Men II#27 (August, 2006) - Craig Kyle, Chris Yost (writers), Paco Medina (pencils), Juan Vlasco (inks), Mike Marts (editor)
New X-Men II#32 (January, 2007) - Craig Kyle (writer), Mike Norton (pencils), Dave Meikis (inks), Nick Lowe (editor)
New X-Men II#35 (April, 2007) - Craig Kyle, Chris Yost (writers), Paco Medina (pencils), Juan Vlasco (inks), Sean Ryan (editor)
New X-Men II#38 (July, 2007) - Craig Kyle, Chris Yost (writers), Skottie Young, Niko Henrichon (pencillers), Sean Parsons (inks), Nick Lowe (editor)
X-Men Manifest Destiny#3/3 (January, 2009) - Chris Yost (writer), Humberto Ramos (pencils), Carlos Cuevas (inks), Nick Lowe (editor)
Dark Avengers/Uncanny X-Men: Utopia#1 (August, 2009) - Matt Fraction (writer), Terry Dodson (pencils), Rachel Dodson (inks), Nick Lowe (editor)
Uncanny X-Men I#513 (September, 2009) - Matt Fraction (writer), Marc Silvestri, Michael Broussaro, Eric Basaldua, Tyler Kirkham, Sheldon Mitchell (pencillers), Joe Weems, Marco Galli, Eric Basaldua, Rick Basaldua, Jason Gorder, Jay Leisten, Sal Regia, Jon Sibal, Ryan Winn (inkers), Nick Lowe (editor)
X-Men Legacy I#226 (September, 2009) - Mike Carey (writer), Dustin Weaver (pencils), Edgar Tadeo (inks), Nick Lowe, Daniel Ketchum (editors)
X-Men Legacy I#227 (October, 2009) - Mike Carey (writer), Dustin Weaver (pencils), Edgar Tadeo (inks), Nick Lowe, Daniel Ketchum (editors)
Dark Avengers#8 (October, 2009) - Matt Fraction (writer), Luke Ross (pencils, inks), Rick Magyar, Mark Pennington (inkers), Tom Brevoort (editor)
Dark Avengers/Uncanny X-Men: Exodus#1 (November, 2009) - Matt Fraction (writer), Mike Deodato Jr. (pencils, inks), Terry Dodson (pencils), Rachel Dodson (inks), Nick Lowe (editor)
X-Men Legacy Annual I#1 (November, 2009) - Mike Carey (writer), Daniel Acuna (pencils, inks), Nick Lowe (editor)
X-Men Legacy I#228 (December, 2009) - Mike Carey (writer), Daniel Acuna (pencils, inks), Nick Lowe (editor)
X-Men Legacy I#230 (February, 2010) - Mike Carey (writer), Daniel Acuna, Mirco Pierfederici (pencils, inks), Nick Lowe (editor)
Nation X#2/1 (March, 2010) - Tim Fish (writer, pencils, inks), Daniel Ketchum (editor)
Nation X: X-Factor#1 (March, 2010) - Peter David (writer), Valentine De Landro (pencils), Pat Davidson (inks), Jody Leheup (editor)
X-Force III#23 (March, 2010) - Craig Kyle, Chris Yost (writers), Clayton Crain (pencils, inks), Jeanine Schaefer (editor)
Phoenix Resurrection: The Return of Jean Grey#4 (March, 2018) - Matthew Rosenberg (writer), Ramon Rosanas (pencils, inks), Mark Paniccia, Christina Harrington, Chris Robinson, Darren Shan (editors)
X-Factor IV#5 (December, 2020) - Leah Williams (writer), David Baldeon (pencils, inks), Jordan D. White, Annalise Bissa (editors)

First Posted: 11/24/2016
Last Updated: 01/19/2021

Any Additions/Corrections? please let me know.

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