Bahssikava is the fabled subterranean empire of the slithzerikai. It has been briefly visited by humans only once, and never explored. Nothing but myths passed down by the exiled sliths tell us about it.
slithzerikai were banished from their lands to Avernum because of Sss-Thss, who was disturbing peace in slithzerikai lands, causing a civil war. Most, if not all, of the followers of Sss-Thoss were originally involved in demon-worshipping to some extent. However, when they became exiled, some were shocked, and began to feel regret for their actions, and thus departed from Sss-Thoss' group of darklings, then establishing Basshikava in hopes of achieving the virtue and peace necessary in someday returning to slithzerikai civilization.
When the banished slithzerikai learn how to live in peace, they can return to their homeland by entering the caves below Lost Bahssikava and open the room that is leading to sealed gates by placing six metal triangles on the wall to make a six-edged star.