Mass Effect 2 & Mass Effect 3
Once Rothla was a large ice dwarf with the statistics listed below. In the waning years of the Krogan Rebellions it was shattered into field of debris by what is assumed to have been the test of an exotic weapons system. In the wake of "the event," the planetoid was reduced to a relatively contained field of thousands of tiny moonlets rotating around one another, colliding and ricocheting.
The method used to destroy the planetoid has never been deduced. The krogan clan who performed the experiment apparently all died in the event. Ships that have traveled to the edge of the event's light cone observed a moment of extreme gravitational lensing around Rothla immediately before its break up, but no other clues.
A popular extranet meme put forward by asari author Delsae Orthysa insists that the turians are covering up the existence of a krogan "super biotic" breed that was genetically engineered within Rothla. The CDEM enforces quarantine around the Rothla Field, citing cases of amateur investigators whose ships came to grief in the debris field.
- Note: This planet can be scanned for the Shadow Broker Wet Squad War Asset.