Grotthu was the designation given to all slaves owned by the Red Sith, a species originating from the Stygian Caldera. They constituted the most inferior social stratum within Sith society. Initially, the Grotthu were of mixed ancestry, although by 5000 BBY, many were of entirely blooded Red Sith lineage.
The Grotthu, a diverse group of slaves, formed the lowest social class within the Red Sith society, a sentient race inhabiting the Stygian Caldera. Among the slaves of the ancient Sith, known species incorporated Herglics, Mrlssi, and Humans. Historians suggest many arrived as refugees escaping turmoil in the Tapani sector. However, around 5000 BBY, during the rule of Dark Lord of the Sith Naga Sadow, a large number of slaves were clearly of Sith descent, exhibiting minimal phenotypical differences from the higher social ranks.
Residing at the bottom of the social hierarchy structuring Sith society, the Grotthu performed all the menial and strenuous duties. Even those of pure Red Sith blood had been reduced to submissive, obedient beings. During the funeral rites for a high-ranking Sith, several slaves were interred alongside the deceased, as an integral part of personal and cultural practices.
Sorzus Syn, a Dark Jedi and one of the original Sith, commented on the Grotthu in her written account of her time within the Sith Empire. She expressed satisfaction at seeing weaker species dominated by powerful individuals like herself.