List of Marvel Comics characters: 0–9

3-D Man
3-D Man was created by writer Roy Thomas and artist Jim Craig. The character was originally created as a tribute to the unsuccessful Harvey Comics character Captain 3-D. 3-D Man was originally supposed to appear as the back-up feature in a stereoscopic comic book featuring Spider-Man, but the idea was cancelled and 3-D Man made his premiere in Marvel Premiere #35 (1977). 3-D Man is described as having three times the strength, speed and physicality of an average man. 3-D Man is the alternate persona of Chuck Chandler, a test pilot who was abducted by the Skrulls. Chandler was imbued with powers by a Skrull artifact during his escape, but the same incident connected him with his brother Hal Chandler, with Hal giving up his energy and going into a coma whenever Chuck needs to access the power of 3-D Man. The character retained his association with the Skrulls, and they became his main adversaries. The original 3-D Man remained an obscure character.

The character of Delroy Garrett was created by Kurt Busiek and George Pérez. The character of Garrett is described as a former Olympic sprinter who joined a cult, the Triune Understanding, after he was disgraced for using steroids. Originally known as Triathlon and first appearing in Avengers #8 (1988), he is given the powers of 3-D Man by the Triune Understanding after they steal them from Chandler. Triathlon joined the Avengers as the new 3-D Man, but he believed himself to be a token hire as he was an African American and the team was being accused of racism at the time they allowed him to join. The character played a prominent role during the Kang Dynasty story arc, but he was unpopular with readers and was not heavily used. He played another prominent role in Avengers: The Initiative #19, in which he joins the Skrull Kill Krew and uses his abilities to see through the disguises of shapeshifting Skrulls. This ability brings him to kill a defecting Skrull who he believed to be hostile.

An alternate version of Chandler's 3-D Man portrayed him as a hero in the 1950s who joined that world's version of the Avengers.

8-Ball
8-Ball was created by Bob Budiansky and Bret Blevins, and first appeared in Sleepwalker #2 (1991). 8-Ball has no superhuman powers. Wearing a spherical helmet designed to look like a billiards 8 ball, he wields a concussive cue stick and exploding balls. Screen Rant listed him among the worst Marvel Comics villains introduced in the 1990s. Jeff Hagees is introduced as a defense contractor and engineer who is also a skilled pool player. He develops problem gambling and adopts the villainous persona of 8-Ball to recoup his losses. Initially a Sleepwalker villain, 8-Ball goes on to fight various superheroes. He did not achieve popularity as a villain, and he was eventually killed off when he was murdered by the Wrecker.

An unnamed character wearing the 8-Ball costume appears in a fight sequence in The Amazing Spider-Man #600. The third version of 8-Ball is introduced in The Superior Spider-Man #26. Created by Dan Slott, Humberto Ramos, and Victor Olazaba, this version of 8-Ball is created by the Hobgoblin when he forms a team of newly created supervillains. The Hagees version of 8-Ball was later resurrected, and for a time he was the cellmate of Moon Knight, giving him another character to interact with and allowing for character growth. Hagees questions his choices in Moon Knight #25 (2023) after luring Moon Knight into a trap: unhappy with his identity as a failed supervillain and the assumptions that this creates about him, he changes his mind and goes back to save Moon Knight.

803
803 is a service robot who joins Agent Venom (Flash Thompson)'s crew. He appears in the series Venom: Space Knight, where he plays a sidekick role. The character was created by Robbie Thompson, who described his history as if "C-3PO had stayed with Jabba for thousands of years", saying that this made the character "self effacing" and "somewhat suicidal". To help Agent Venom move without his legs, 803 builds him a set of prosthetic legs. This idea inspired editor Jake Thomas to focus on the wounded veteran aspect of Thompson's character, including a partnership between Marvel Comics and the Wounded Warrior Project.