The Black Hearts were a group of all-female mercenaries founded and run by Molotov Cocktease.
The Black Hearts started as a group of female assassins-for-hire led by Molotov Cocktease. Molotov then hired the O.S.I.'s top assassins to kill her ex-lover Brock Samson in order to eliminate their competition, but inadvertently caused a confrontation between the O.S.I. and The Monarch's Fluttering Horde.
Season 4 Edit
In the Season 4 finale Operation P.R.O.M., all the other members of the Black Hearts were used to infiltrate the prom for Hank and Dean, with Molotov giving them the mission of killing everyone at the stroke of midnight/12:00 A:M. As Brock rushed back he found that Rusty had used an experimental "spanish fly" on all of them to cause uncontrollable arousal. The drug worked at first, causing everybody to act loving and sedate until they mutated into a horde of fly monsters who spat acid. Brock and the other combatants at the party killed all of them off screen, leaving Molotov the only surviving member of her organization.
Season 5 Edit
Molotov Cocktease appeared in the Season 5 episode O.S.I. Love You running a solo covert mission on behalf of the OSI to rid their organization of moles and infiltrators. With her agreement to serve as a free agent for OSI wetwork in the future, it seems The Black Hearts may be permanently disbanded.
- In keeping with the show's running gag of associating popular music acts with supervillains, the group's name most likely comes from the female-fronted hard rock band Joan Jett & the Blackhearts.