List of Marvel Comics characters: O
He was a wisecracking, bully-wannabe who joined athlete Flash Thompson to pick on unpopular kids such as Peter Parker. When Spider-Man appeared throughout the years, Seymour was still a sort of harasser to Peter as time goes by; for instance, he began playing some pranks on Peter such as putting a "kick-me" sign on his back and trying to give him a "wedgie". He makes a final appearance in the Marvel Knights Spider-Man series in issue #7 where he once again troubles Peter and he meets his demise when he is killed by Angelo Fortunato, the son of crime boss Don Fortunato who became the new Venom. Peter and his wife Mary Jane Watson were testified regarding O'Reilly's death to the police who arrive at Peter's high school reunion due to O'Reilly's demise.
- Solomon O'Sullivan
- Obnoxio the Clown
- Gengi Odashu
Within the context of the stories, Aleta is a member of the Guardians of the Galaxy.
Within the stories, Old Skull is born in 1987 in an alternate-future Earth designated Earth-691 by Marvel Comics. In 2001 he is enslaved by the Martians and put to work as a laborer converting existing buildings into Martian bases. Eventually he is consigned to the gladiatorial arena and becomes a champion by 2010. He meets Killraven in the Madison Square Garden Arena in 2014. Eventually the pair escape from the Gladiatorial Institute, and Old Skull joins Killraven's Freemen.[volume & issue needed]
Much later, Old Skull is bitten by a zombie created when the cross-reality traveling Machine Man and Howard the Duck unleash a zombie infestation to drive the Martians from Earth. Killraven successfully manages to avoid his transformation into a zombie by severing the arm.
- Omega ll (Scramble)
- Omega lll (Collective, Weapon Omega ll)
- Omega Red
- Omega Red ll
- Omega the Unknown
- Omerta ll (Paulie Provenzano)
One Above All
Within the context of the stories, the One Above All is the leader of the Celestials and is present during the Fourth Host to visit Earth. The one above all is the most powerful character In the entire marvel universe. He is the responsible for the existence of all life in the Marvel universe and possibly beyond. The One-Above-All is the master and sole superior of the cosmic overseer and arbitrator known as The Living Tribunal. 
Oneg the Prober
Other versions of Oneg
- Onslaught (Imperial Guard)
- Onslaught ll
The character subsequently appears in Thor #9 (March 1999), #14 (August 1999), #20 (February 2000), #22-25 (April-July 2000), and #41-42 (November-December 2001).
Orikal is an extra-dimensional being who has mystical powers so vast that they can nullify the power of Odin. Orikal has incredibly advanced scientific knowledge, and his "Infinite Eye" can see everything that is happening in the world he is in, as well as what will happen in its alternate futures.
Orikal was trapped within a sea of flame by Geirrodur, King of the Trolls. Geirrodur coerced Orikal into providing information on how to build advanced weaponry, which the trolls used to invade Asgard. The trolls used one of their devices to drain the power from Odin's scepter, and the Asgardians were on the verge of defeat. Thor and Sif managed to find Orikal but Ulik tried to kill Orikal. Thor defeated Ulik and freed Orikal, who transformed into energy and shot out into space.Template:Vol. 1, issue 139, 1966
Orikal later became enslaved by Geirrodur once again. He provided information to Thor, Ulik, Odin, and assisted Thor's efforts to defeat Mangog and prevent Thanos from using the Chalice of Ruins and the tears of the Designate to gain vast power and destroy all life in the cosmos.[volume & issue needed]
Orrgo is a fictional character from the Marvel Universe who first appeared in Strange Tales #90 (Nov. 1961).
Orrgo is an extraterrestrial "space god", who arrived on Earth and has tried to conquer it many times in the past. He was recently summoned by the Headsmen and controlled by the God from Beyond statue. Through unknown means, Orrgo was captured by S.H.I.E.L.D. and recently placed in the Howling Commandos Monster Force.
Adam Able’s home planet was called "Orrgo" in Journey into Mystery #82.
Amberson Osborn is a Marvel Comics character introduced in The Spectacular Spider-Man Annual #14 (June 1994). He was Norman Osborn's father. Amberson was a brilliant inventor, but lost the family fortune when his invention was stolen yet often "blamed others for his failures". Unfortunately for Norman and his mother (Amberson's wife), he began abusing alcohol after realizing that he was cheated. Amberson lashed out at and verbally abused Norman, and even hit his wife when she came to their young son's defense. Amberson also locked Norman in an abandoned family mansion to force his son to "face the darkness" and made him stay there throughout the night during an intense rain storm which traumatized Norman from the apparent cackling of a green goblin-like creature.
Alternate versions of Amberson Osborn
Emily Osborn is a Marvel Comics character introduced in The Spectacular Spider-Man #180 (September 1991). She was Norman Osborn's wife and Harry Osborn's mother. Emily was apparently the only person that Norman ever showed love to but their son's birth had weakened her and she passed away sometime after.
Emily Osborn in other media
In the 2002 Spider-Man movie, a picture of Emily Osborn can be seen in Norman Osborn's room.
- Harry Osborn (Green Goblin ll, American Son)
- Norman Osborn (Green Goblin, Iron Patriot, Goblin King)
- Normie Osborn
- Outlaw Kid
Richard Rennselaer is a former S.H.I.E.L.D. agent whose son developed nuclear psychosis, a total withdrawal from reality due to a fear that the world will end at any moment due to nuclear destruction.[volume & issue needed]
Desperate to help his son, Rennselaer (secretly a mutant with the power to control machinery) took on the codename of "Overrider" and stole the experimental TESS-One robot - part of a 1939 project dubbed Total Elimination Of Super-Soldiers which was intended to be a failsafe against the Super Soldier program. Overrider had the TESS-One robot coated with adamantium at the Adametco Metallurgy company, and it was there he first encountered Captain America and Wolverine, each who had been following different leads. Overrider escaped with TESS-One, and later mounted an assault on a nuclear command facility in the hope of launching America's entire stockpile of nuclear missiles and burying them in the ocean floor, not caring that Moscow may interpret the launch as an attack on the Soviet Union. Captain America and Wolverine teamed up to defeat TESS-One, and then encountered Overrider as he was about to launch the missiles. Captain America knocked Overrider off his flying sled with his shield, and Wolverine almost impaled him on his claws as he fell, choosing instead at the last second to let Overrider fall to the floor. Overrider was quickly given medical attention and then taken into custody.[volume & issue needed] Overrider was depowered thanks to the effects of M-Day.[volume & issue needed]
- Fred Van Lente (w), Kano (p). Marvel Zombies 5 2 (June 2010), Marvel Comics
- Jack Kirby (w), Jack Kirby (p), John Verpoorten (i). "The Fourth Host" The Eternals 7 (January 1977)
- Mark Gruenwald, Ralph Macchio (w), Keith Pollard (p), Gene Day (i). "Chapter One Twilight of the Gods!" Thor 300 (October 1980), Marvel Comics
- Mark Gruenwald (w), Ron Wilson (p), Chic Stone (i). "The First Celestial Host!" What If... 23 (October 1980), Marvel Comics
- Jack Kirby (w), Jack Kirby (p), Mike Royer (i). "The Killing Machine" The Eternals 9 (March 1977)
- Ultimate Spider-Man #73
- The Spectacular Spider-Man #180
- Ultimate Spider-Man #3
- Ultimate Spider-Man #4