An alliance of a multitude of Jaffa women formerly under the banner of the Goa'uld Moloc. The women formed a secret rebellion against Moloc under the command of Ishta, who still serves as his high priestess. When Moloc began murdering all infant girls born to the Jaffa in his service, Ishta -- who was called upon to preside over the Ceremony of Fire -- began smuggling the children into safety on the planet Hak'tyl.
The women have received training as warriors, and are expected to defend their homeworld if it comes under attack. Originally the Hak'tyl stole symbiotes from other Jaffa to survive, but they were eventually convinced by SG-1 to rely on tretonin as an alternative to their dependence on the Goa'uld.
Eventually the resistance members came to accept outsides, and with Ishta's persuasion formed an alliance with Earth. With the destruction of Moloc and the downfall of the Goa'uld they were presumably integrated into the newly formed Free Jaffa Nation, with one of their own -- Ka'lel -- appointed to the Jaffa High Council.
See also: Jaffa resistance, Free Jaffa Nation
Birthright - SG-1 encounters the Hak'tyl resistance, who are eager to form an alliance.
Sacrifices - The Hak'tyl move against Moloc, but Ishta is captured. Teal'c's son Rya'c is married to a young Hak'tyl woman.
Ex Deus Machina - Ka'lel, once a member of the Hak'tyl under Ishta's leadership, now sits on the newly formed council of the Free Jaffa Nation.