The System Lords including Lord Yu came up with a plan to trap Helios forever instead of killing him so they could share his domain between them, the system Lords tricked Helios to a Asgard protected planet by Bribing one of Helios' Daughters, his Daughter told Helios about this planet saying it had ancient weapons and millions of humans, The System Lords promised Helios' Daughter half of his domain and his position as System Lord.
Helios went to this planet through the stargate fearing another Gou'ald might get there before him, Helios and 50 of his most loyal Jaffa ended up inside a deep dark cave with only 1 way out, the only door was blocked by a forcefield which didnt allow Gou'ald out of the cave.
Helios and his Jaffa were traped in the Cave for 50 years eating any wild animal that came into the gave and drinking there Blood and any water that leaked through the rocks. After 50 years of nothing, The 50 Jaffa became disloyal Believeing Helios wasnt as powerfull as they once thought, The 50 Jaffa tryed to leave by taking out there Symbiots hoping to get new ones quicly so they could survive but the Jaffa died before they could get to the stargate.
Helios spent another 400 years in the cave only to be let free after the power supply failed on the forcefield, Helios escaped and took a new host almost immidiatly, a Boy No older then 20 who was hunting in the forest on the planet he was traped on. Helios left the planet hoping he could regain his empire but after finding out it was all a trick from the system lords he knew he would never be allowed back untill younger Gou'ald take there place as system lords.
The System Lords didnt honor there agreement by giving Helios' Daughter half of his empire, they killed His daughter and split the empire fairly between them. More years went by and Helios hasnt been heard from some believe he died others believe hes waiting for the right time.
Most of Helios' Domain is made up of the same planets belonging to Lord Pyrrhus and he feels they are rightfully his and plans to retake his domain and become the most dominant Gou'ald in the galaxy once again.