brief summary of the ancestors life stories, far as we know? what do we know about the psiioniic, specifically?

You can find a summary of the Ancestor’s lives here. The Psiioniic was a gifted psionic who was a slave before he became a follower of the Signless. After the death of the Signless, the Psiioniic was grafted to the flagship of the Condesce. She extended his life span with her touch and eventually died as a result of the Vast Glub.