The player meets Lyris Titanborn at the beginning of the game in The Wailing Prison. She's one of the Five Companions, who sought the Amulet of Kings, to persuade Akatosh into accepting their leader as the Dragonborn. Lyris is a Nord warrior from Skyrim. It is assumed the blood of Giants runs in her lineage. She was Varen Aquilarios' personal bodyguard, before the treason of Mannimarco.
Lyris sacrifices herself to free The Prophet from his prison, so he and the player can flee Coldharbour.