Jeremy Payne, operating under the moniker Grimm, was an infamous criminal marked by documented mental instability and a string of killings. His arrest by Detective James Blood ignited a deep personal vendetta against the officer. Though officially sentenced to death and presumed deceased after imprisonment, Grimm resurfaced as a test subject for the LIVE Corporation's experimental mask project.

The mask granted Grimm supernatural abilities: rapid healing, the power to alter his facial appearance at will, and immunity to pain, significantly enhancing his combat durability. Consumed by obsession and instability, he targeted James Blood and launched a violent assault on SSC headquarters, killing numerous police officers in a rampage. This established him as the series' first major antagonist.

Grimm exhibited extreme derangement, fixated on using blood—both his own and his victims'—to create paintings, reflecting a twisted artistry. He frequently displayed a menacing slasher smile during confrontations, underscoring his volatile nature. His real identity appeared only briefly in official records.

His background included a period as an aspiring artist before financial struggles led him into criminal activities and eventual recruitment by a secretive organization. This history added a layer of tragedy to his character, though secondary to his role as a relentless killer. Grimm died during the events of the SSC attack, with no subsequent mentions in later arcs or spin-off media. His mask abilities and abrupt end positioned him as the introductory antagonist whose actions catalyzed the broader investigation into the mask conspiracy.