Myzrael

Myzreal is a titanic watcher from the popular MMORPG World Of Warcraft, she acts as a boss following a fairly lengthy quest chain in which she tricks the player into aiding her escape her imprisonment undergound, pretending to be a princess - however when summoned her true form is revealed as a towering giantess, displeased with being summoned early she quickly turns on the player and tries to kill them but is defeated.

According to lore Myzreal was once one of the many creations of the godlike Titans and protected Azeroth until she was driven mad by the whisperings of the Old Ones - in order to protect Azeroth from the insane giantess the mountain giants imprisoned her deep underground and she could only communicate with the world via crystals, which is how she contacted the player - feigning helplessness when in reality she is a fairly powerful being.