Some TMNT stuff really isn't for little kids.
In the IDW continuity, Diamond is a human-born mutant porcupine and mutagen bomb victim who, during the six-month time skip between issue #100: City at War, part 8 and issue #101, became one of the residents in the newly-quarantined Manhattan neighborhood of Mutant Town. Diamond, along with some other fellow mutants such as Puggle and Bandit, was recruited into Old Hob's Mighty Mutanimals to help enforce Hob's interests within the neighborhood's walls.
In issue #101, Puggle and Bandit caught Mona Lisa carrying an unauthorized quantity of food which she had actually stolen from the Mutanimals' food bank, which Mona had intended to donate to Alopex's shelter. The two enforcers started trying to rough Mona up, but Jennika came to her rescue and easily defeated the enforcers. But Puggle and Bandit returned with Diamond, an even more powerful enforcer, and Diamond severely injured Jenny as the other two enforcers seized Mona. In issue #102, Sally Pride, a Mutanimals commander, was on a nearby rooftop visiting with Raphael and Pepperoni when they witnessed the fight. As Diamond was openly pondering whether to kill Jenny, Sally stepped in and disciplined the enforcers, announcing their impending demerits and terminating Diamond's employment on the spot.
Diamond returned to Old Hob trying to get her job back, pleading that she had no food or money without it, but Hob agreed with Sally's judgment and refused to rehire Diamond. Diamond got out of Hob's sight, but lingered long enough to spy on him meeting up with Koya and some Foot Ninja to discuss a shady deal: Hob had secretly mutated three weasels to trade to Oroku Karai for Foot Clan recruitness in exchange for food, ammunition and winter gear. As Hob and Koya stepped into another room to argue over transit arrangements, Diamond opened the weasels' crate to release them, but the weasels unexpectedly attacked and bit her. Hob was ready to shoot Diamond execution-style, but Koya called on Hob to help her recapture the weasels.
- Diamond's design was based on an unnamed mutant porcupine artwork drawn by Kevin Eastman and Peter Laird which appeared in Teenage Mutant Ninja Turtles & Other Strangeness, published in 1985 by Palladium Books.
- Diamond's gender is visually ambiguous, as she has no visible secondary sexual characteristics. Her gender can only first be inferred in issue #102 when Jennika, commenting on Diamond, says, "I hate her," just before Alopex pulls out another of Diamond's porcupine quills stuck in Jenny's head.