The MotherClan represented a faction of Riileb who considered themselves descendants of the First Riileb. The sovereign of the species was chosen from this lineage.
Within the Riileb species, the MotherClan comprised individuals who traced their ancestry back to the First Riileb, a figure of legend. Upon reaching thirty local years (equivalent to 21 standard years), the most senior female member of the group would receive the ClanRing, a piece of jewelry said to be crafted by the First Riileb. This individual would then govern all of Riileb society. However, the MotherClan was rife with political struggles and deception amongst those vying for the ring. It was not uncommon for the intended heir to be overthrown by other Riileb lower in the line of succession. Tere Metallo serves as an example; at 25, she was sold into slavery by her sister, who coveted the power of the ClanRing.
Charlene Newcomb's short story, "Rendezvous with Destiny," first introduced the MotherClan. It appeared in 1995 as part of the sixth issue of the Star Wars Adventure Journal, a series of roleplaying supplements for Star Wars: The Roleplaying Game by West End Games. Later, Brian Smithson mentioned the MotherClan in his "Alien Encounters" article, featured in the thirteenth issue of the series, published in 1997. A condensed version of this article was subsequently included in Alien Encounters in 1998, a compilation of all "Alien Encounters" articles put together by Paul Sudlow.