Grunchlk was an opportunistic businessman who served as a go-between and translator for Diagnosans. Grunchlk's instincts for self-preservation have made him an expert manipulator, and willing to make deals within deals, counterdeals, and double crosses to ensure that he always comes out on top.
After Moya was burned to dispose of an infestation of Karack metalites, her crew made a deal to have Diagnosan Tocot treat her burns. Grunchlk also arranged for Tocot to remove the neural implant that Scorpius had put in John Crichton's head during his torture with the Aurora Chair.
Unbeknownst to the crew of Moya, a Scarran soldier had also arrived on the planet with his own interests in Crichton and Grunchlk had also made a deal with him. This was complicated by the arrival of Scorpius during Crichton's operation. To save his deals, Grunchlk put the Scarran in a cryogenic tube.
Scorpius made an attempt to control the situation -- putting an implant in Grunchlk that put him entirely under the Peacekeeper's control. Chaos ensued when, believing the cryogenic tube was malfunctioning, Tocot released the Scarran from stasis. Feeling betrayed, the Scarran put Grunchlk inside the pod. Stark determined that Grunchlk was "effectively dead".
This proved to be less than accurate, as Grunchlk was later awoken. During the Peacekeeper/Scarran War, Grunchlk arrived on Qujaga alongside Chiana. Amidst the conflict, it seemed Grunchlk had betrayed the crew to the Scarran Empire -- though it turned out to be Sikozu's doing. When Qujaga was evacuated, both Grunchlk and Sikozu were left behind. The two survived, and managed to eventually escape the planet.
Grunchlk is derived from Farscape.