Appearing in "Circle of Four: Part One"
- Venom (Flash Thompson)
- Ghost Rider (Alejandra) (Possessed by the Spirit of Vengeance)
- Red Hulk (Thunderbolt Ross)
- X-23 (Laura Kinney)
- Gari Oyle (First appearance)
- Symbiote Warriors (First appearance)
- Antitheses (First appearance)
- Betty Brant (Behind the scenes)
- Rosie Thompson (Mentioned)
- U.S. Army (Named only)
- Gary Rags (Only appearance; dies)
- Gary Rags' mother, wife, and sons (Mentioned)
- Toxin (Pat Mulligan) (Mentioned) (Deceased)
- Son of Satan (Daimon Hellstrom) (Mentioned)
- Harrison Thompson (Photo)
- Dante Alighieri (Mentioned)
- Doctor Strange (Stephen Strange) (Mentioned)
- Mephisto (Appears on a computer screen, TV, or hologram only)
- Avengers (Mentioned)
Races and Species:
- Mephisto's Realm (Appears on a computer screen, TV, or hologram only)
- Venom Symbiote
- H'elian's Mirror Cauldron (First appearance)
- Adamantium (On X-23's claws)
- Toxin Symbiote (Mentioned)
Synopsis for "Circle of Four: Part One"
Still in Las Vegas, Flash angrily throws his motel room's phone against the wall after having a fight with Betty.
At the Devil's Den casino, two goons drag a man who owes money to the casino into the owner's office. The owner, Mr. Degli, offers to absolve all his debts to the casino in exchange for his soul. The man agrees to the deal and his soul is taken by Mr. Degli.
In the Nevada desert, Johnny Blaze is trying to teach Alejandra, the new Ghost Rider, a motorcycle trick but she is mad that he has the nerve to try to teach her something. At the same time, Red Hulk is stomping around the desert in search of Flash.
X-23, in disguise as an employee of the Devil's Den, is searching for Mr. Degli for stealing a vial of her blood.
Mr. Degli and his girlfriend Ms. Oyle enter a construction site that is covering up a large, satanic machine. Mr. Degli puts in all the ingredients required to power it, 100 human souls, a vial of the Toxin symbiote, and the blood of a mortal who has been to hell and back, X-23's blood. All that's left is one final ingredient.
At a diner, Alejandra is angry that Johnny assumes he knows more than she does. Suddenly, she feels hundreds of cursed souls and leaves without Blaze while he calls Daimon Hellstrom to investigate it.
In his motel room, Flash's drinking is interrupted when Red Hulk smashes in. The symbiote bonds briefly with Red Hulk and forces him to go to a gas station, which blows up. Venom returns to Flash but he is too drunk and the only way to sober up is to let the symbiote take control, something he is not willing to do. Regardless, Red Hulk catches up to him and resumes their fight.
Meanwhile, X-23 finds a lab that contains clones of her, made from her blood. But before she gets a chance to destroy them, they break loose and have bonded with symbiotes.
Ghost Rider reaches the construction site and drives in the opposite direction that the device is turning. However, this instead activates it, summoning demons from Hell to Earth. And to make matters worse, if she stops, the portal will drag Earth into Hell.
As Hell continues to spread through Las Vegas, Venom and Red Hulk decide to stop fighting and work together to stop the one that caused this, who Red Hulk suspects is hiding within a black tower off in the distance. Johnny rides to Las Vegas and places the amulet he took from Hawkeye onto the entrance, preventing Hell from spreading. Mr. Degli senses that something has stopped Hell from consuming the Earth but nevertheless returns to his black tower and reveals himself to be Blackheart, while Ms. Oyle turns into a gargoyle.
Johnny finds the Ghost Rider riding around the doorway and takes her place so that she can stop Blackheart.
In the black tower, Blackheart stands beside a mirror that he is sure will stop the heroes if they come after him. X-23 and the symbiote clones come crashing in, followed shortly by Venom, Red Hulk, and Ghost Rider. To stop them, Blackheart activates the mirror, which creates the group's antitheses, opposites of who they are: Ichor, an angel, X-666, a cheerleader, the Evangelist, a pastor, and Encephalon, a giant brain.
- PART ONE OF A SIX PART EVENT!