A villain named Dr. Sugarman broke into his lab and tried to steal the virus. David was injured and injected with the untested virus. He became Xombi, a technologically enhanced human being who battles the Shadow Worlds. At one point he was part of Star Chamber with Rocket, and has appeared since the merger of the Dakotaverse into the DC universe.
He was the first Milestone character to confront Dr. Nemo.
The Brave and the Bold
Xombi even team-up with The Spectre.
Xombi was originally set to appear in the upcoming Milestone revival "Earth M" series in 2018. As of August 22nd 2020, Xombi will return to mainstream in February 2021. An online sampler, Milestone Returns Zero, was released online for free at DC Fandome on September 12th 2020. It is revealed that Xombi's origin story was retcon. Instead of being solo, this time he is joined by female companion, Kelly Sanborne, who together are called "Duo".
An alternate version of David Kim, created in an alternate timeline by Anansi, appears as an Green Lantern and as a member of the Justice League of America.