- "I die free, brother."
- ―Sebe't last words[src]
He grew up in a village on Chulak across the hills from the village where Teal'c was born. He was trained simultaneously with Teal'c under Master Bratac. The two fought and bled during many campaigns, mainly against Cronus and Bastet. The two were rivals, it seemed, from the start, and their paths were ultimately destined to cross. He was made First Prime of Apophis after Teal'c betrayed his master and defected to the Tau'ri. He was previously married to Li'tel, who committed suicide after Apophis, who took her as a lover, grew bored of her and tossed her away. She jumped from a bridge near the palace and Apophis lead Sebe't to believe that it was an accident. Later, he grew to believe that Teal'c had killed her, when in actuality, Apophis ordered Teal'c to keep quiet about the real details of her death.
In 2001, he was on P5J-818 with a handful of Jaffa and a Ha'tak and lead an ambush on SG-1. After having captured Jack O'Neill and Daniel Jackson, he lied in wait. Teal'c first encounted him as he infiltrated the Ha'tak in search of his companions. Disguised as a serpent guard, he was attacked by Teal'c. After Teal'c removed his helmet, he was poised to kill him, a knife raised in a killing blow, but Teal'c could not do it. He tricked Teal'c into thinking that he thought that the Goa'uld were not gods. Upon rescuing his friends, Teal'c once more encountered him. After a quick gloat, Sebe't stunned him, calling him Shol'va. Teal'c would learn seconds before that it was he who led the ambush against SG-1 and fired the blast that lead to the injury to Samantha Carter's shoulder. Teal'c had been betrayed by his old friend.
He took Teal'c few kilometers away from the ship and deposited him in an isolated location. The two exchanged insults, then Sebe't challenged him to a duel to the death to prove he, not Teal'c, is worthy as First Prime, and to kill Teal'c and please his master. The battle commenses, and Teal'c quickly gains the upper hand. Fearing defeat, he uses an Altir, an implant used by the Goa'uld in their gladiatorial arenas, which was implanted on Teal'c as he was unconscious, so he could defeat his superior opponent. The fighting is fierce, with Sebe't blocking every attack and critically wounding Teal'c, but Teal'c manages to escape. After healing, he once again frees his friends who then made it to the Earth. Teal'c does not follow, and removes the DHD's control crystal. He and Sebe't fought one last time, and Teal'c finally gets through to him. Teal'c explained everything about Li'tel to Sebe't, how Apophis lied to him and used him; at first, Sebe't does not believe him. With the help of the Altir, which connects the two's minds, Sebe't sees it all, and finally believes Teal'c. Just as soon as he renounces his master, his Altir, which is programmed to kill it's wearer upon disloyalty, begins killing him. Only after he curses his god, he dies, but he dies free. Teal'c then is able to remove his own Altir and leaves the planet. Sebe't has died free, and has died a true friend and brother of Teal'c. (SG1: "First Prime")