Some TMNT stuff really isn't for little kids.
In the IDW continuity, Darius Dun is the financier and boss of the Street Phantoms. Although he was a gifted athlete in his high school days, Dun recognized early on his business acumen and the advantage he could create through the right contacts. This was one of the reasons that he commissioned the inventor Libby Meitner, seeking to get a grip on the underworld of New York City with her scientific talents.
His plans to consolidate his criminal empire led to fierce warfare with the Foot Clan under Splinter's leadership. Even though their high-tech weapons first gave the Phantoms an enormous advantage, the Ninja Turtles were able to re-establish the rift with the help of Libby's ex-husband Harold Lillja. In the end, the Foot Clan defeated the Phantoms.
In issue #64, Darius Dun was captured during a raid by Splinter's Foot Clan. Splinter offered to spare Dun's life if he surrenders all of his assets to the Foot Clan, but Dun refused. Splinter then coldly ordered Jennika to execute Dun on the spot. This killing prompted Splinter's sons, Leonardo, Raphael and Donatello to cut ties with Splinter and the Foot Clan, which Michelangelo had already done in issue #50.
However, Dun was not finished with the Turtles. In Teenage Mutant Ninja Turtles/Ghostbusters 2, he returned as an angry ghost who summoned the interdimensional demons known as the Collectors and sent them after the Turtles. His original goal was to imprison them for the rest of Splinter's life, and watch Splinter's agony at never knowing what happened to his sons.
When he summoned the Collectors for the second time in order to berate them for their failure, they devoured him. However, his essence possessed them and transformed all four into a new entity who was both Darius Dun and the Collectors.
- Unlike his original character from the Fast Forward series, this version of Dun has no apparent relationship to the Jones Family.