After the Space Gem chose Quantum to be its host, he was taken in by Assessor to be experimented on for the Beyond Corporation's superhuman experiments.
Quantum debuted in Miles Morales: Spider-Man #7. He was a spinoff of the Infinity Wars event, which ended with Adam Warlock imbuing the Infinity Gems with the ability to choose their own destinies. He was introduced ahead of the Infinite Destinies event that would chronicle the Gems' new chosen ones, but Infinite Destinies was delayed due to the global COVID-19 pandemic, leaving a decent sized gap between his first appearance and the publishing of the event.
Major Story Arcs
After Quantum came into contact with the Space Stone, he sought out Assessor, an artificially intelligent analyst, whose purpose is to test the capabilities of select superhumans. He went to work as an enforcer for the Assessor in exchange for the Assessor figuring out a way to remove the stone from him.
The Assessor used Quantum's abilities to trap Miles Morales and measure his abilities. After Miles is rescued by his dad and uncle, he confides in Iron Man what happened, causing Iron Man to try and shut them down. Iron Man succeeded where Assessor failed, synching his tech with Quantum's power signature and nullifying his power long enough to knock him out.
As part of Black Cat's plan to assemble the Infinity Stone hosts, she gave Quantum a device that would hide him from Nick Fury, who was attempting to apprehend the hosts. Cat had a plan to bring together a few hosts to increase their power. She set up Quantum to be in close proximity to Star, so she could use her amped up powers to cure Cat's mom of cancer. Unfortunately, the hospital was a plant created by Fury, full of mercenaries. This forced Quantum to escape on his own.
When Miles and his clone brother, Shift, were looking into Beyond leads, they found the Assessor's new hideout. The Assessor was working for Beyond creating and/or stress testing superhumans for Beyond's experiments, including Quantum. He was forced to fight Miles yet again, but when Miles found out the truth, he backed down. This show of mercy inspired Quantum to turn against the Assessor. Using his teleportation, he got Miles to the Assessor's main terminal, where he stores his A.I. There Miles was able to overload it with a venom strike, wiping the Assessor from it.
Now free, Quantum teleported away but first told Miles to check the "black doors," where Miles finds the info that he had been looking for.
Space Stone: Quantum is able to manipulate space, teleporting and opening portals. He also has a series of a open spaces as part of his physical person.
- Infinity Circuit: The closer he is to other Infinity Hosts, the stronger he becomes. "Powered by the user's mastery of Power. Can allow teleportation through space"