|Played By:||Richard Dean Anderson, Kyle Graham|
Unity, a crystalline form of Jack O'Neill that came to Earth to find what was hurting Jack the most. When Jack touched the entity, he was thrown back and knocked unconscious.
The Crystalline unity probed his mind, and saw that he had an empty space where his Son once was. In fear that his friends would destroy it, the unity took his form, and went through the Stargate to bring Charlie O'Neill back. Once there he realised that death meant that they no longer had a physical form.
However due to the difference in the planets, the Unity was beginning to "decay" and releasing dangerous radiation. When the SGC realised what had happened they went looking for the unity and found that he had been taken to hospital.
Once there Jack spoke to it and the Unity helped Jack move on with his life. SG1 then sent him back home where the unity could remain stable.