Commander Vale is an NPC in Torchlight II. She is a leader of the Vanquishers, who serves as a quest giver in Act 1.
In fact, Vale is the Vanquisher player character from the first Torchlight. Following the destruction of the town of Torchlight, she follows the Alchemist into the Wellspring Temple in order to protect the Guardian of Water. She is overwhelmed by General Grell and his minions, but is rescued by the player.
Vale then returns to the Estherian Enclave, where she greets the player and offers a new quest: to follow the Grand Regent to the Watchweald Temple and keep him from infecting the Guardian of the Wild.
After this, she serves as the Skill re-trainer in Act III, residing in the Imperial Camp in Grunnheim.