Very little about Shrapnel's past and identity is known, although it is known that his name is Mark Scheffer and that he was a normal human at one time and has an ex-wife and two very human blond-haired daughters. Shrapnel has tried to stay incognito, but failed to do so after deciding to slaughter anyone who caught even a glimpse of him.
He was discovered by the Doom Patrol in Kansas while on a murder spree and forced into combat by the team. Celsius quickly flooded Shrapnel encasing him within a solid prison block of ice. Shrapnel blew it apart, hitting Mrs. Caulder point blank and hospitalizing the heroine.
It is also noted that Lodestone was not able to magnetize some control over Shrapnel. It was energy blasting Tempest who worked out that Shrapnel is a series of organic cells creating a single consciousness- that feeds on the blood of victims. Shrapnel escaped the encounter with the Doom Patrol.
In DC Special: Cyborg mini-series, Shrapnel has joined The Cyborg Revenge Squad.
Following the Final Crisis, he was with Cheetah III's Secret Society of Super Villains at the time when Genocide was created. He was defeated by Wonder Woman.
Shrapnel appeared in the intercompany crossover JLA/Avengers as one of the villains who attack the Vision and Aquaman in Metropolis. He actually makes the first attack, but the Vision blocks it by increasing his density. After the two heroes are subdued, Shrapnel prepares to blast Aquaman when Green Lantern attacks him and knocks him out.
In other media
Shrapnel appeared in the Batman: The Brave and the Bold episode "When OMAC Attacks!" voiced by Greg Ellis. This version of Shrapnel is originally General Kafka (inspired by the eponymous future villain in the OMAC comic book series), a Russian war criminal who was turned into an organic metal being through a lab accident. As Shrapnel, he continuously fights OMAC in a destructive battle arranged by Equinox. Shrapnel is driven by revenge. He claims to hail from a poor Russian village that was razed and burnt to the ground during an unspecified conflict (apparently as collateral damage in failed attempt of the GPA to curb Kafka's power base), dooming its farmer inhabitants (or better the survived ones) to poverty and famine. In this precarious state of mind, Shrapnel is exploited by Equinox coaxed into trying to set up a meltdown to burn New York City into a nuclear holocaust as a balance for the earlier loss of his people. He was defeated by OMAC and Batman.
Mark Scheffer appeared in Arrow, portrayed by Sean Maher. In "Blast Radius", he is an anti-government serial bomber, part of a terrorist militia group. Team Arrow identifies him by analyzing the remains of his explosive devices. Scheffer uses the alias "Shrapnel", but the character otherwise does not resemble the comic book version. After bombing two government buildings in Starling, Shrapnel targets Sebastian Blood's Unity Rally. He is interrupted by the Arrow, who pursues and apprehends him. In the episode "Suicide Squad", Scheffer is a reluctant member of the Suicide Squad which ties in with the title. Shrapnel tries to abandon the team on their first mission, unaware of a failsafe bomb implanted in his head by Amanda Waller. Waller detonates the bomb, killing him.
Shrapnel (New Earth)
Shrapnel (Prime Earth)
Shrapnel fights Superman with other supervillains
Shrapnel with other supervillains as part of the Cyborg Revenge Squad