He was born from the D.N.A of Dalek Thay and Jast. He created The New Cult Of Skaro (Cult M.2) consisting of H4er3, Dalek Trump, Dalek Fire and Dalek Robb. They warped through time and ended up on Mars where they plotted to destoy Earth using a Newron Gun but The 17th Doctor and Jack Harkness destroyed his base by rewiring it. Tet and the others survived and escaped. (DW:Mark 2)
It was later revelved when he met the Doctor and Whem on New Earth that Davros created him. The Cult planned to burn New Earthu up. The Doctor designed a weapon and without mercy he attacked and killed all the Cult except Tet who escaped. (DW:Daleks on New Earth)
He used temporal shift and ended up in a dumpster. (Dalek Stories: Tet.)
He was stranded onEarth for 2 years. (Dalek Stories Tet)
Heb encountered the 20th Doctor and hunted him but ended up falling down a cliff and perishing. The Doc was not aware anything was happening. (DWBIT:The Unknown Assasian)
Behind The Scenes
.His televised fate is unknown to many fans.