Not even Slab knows how he got onto Dusk in the first place; as a child he was found in the middle of a settlement after a scheduled supply drop and mistaken for a dimwitted teenager due to his stature. As Slab reached maturity, the elders soon realised that he was not, in fact, an unusually large and stupid adult, but instead an "Og-Grin" from the legends of the Tithe spread by some of the few Guardsmen who actually managed to survive their service and return to Dusk. As a result, Slab was offered up along with the rest of their tithe in the hopes that the Emperor would guide him back to where he came from.

Slab's Comrade Claire is a heavyset young woman with a homely beauty to her, who seems to have adopted him as a replacement for her little brothers whom she had to leave behind on Dusk. She's often found fussing over him and making sure he's presentable; just like a naggy but caring big sister would.