"The end-game credits tells that there is a voice actress for Young (Child) and Old (Not mentioned, it was blank.) Shanalotte. Could she be the Firekeeper from the CG intro? She tells us that it's her own manifestation who bring us in Drangleic." Something else that supports this theory is that, in the opening cinematic, the firekeeper says "Without really knowing why". Emerald Herald says the exact same phrase to you in Undead Crypt after picking up the King's Ring.