The Corsair

The Corsair was a Time Lord described by the Eleventh Doctor as "one of the good ones". His signature emblem was a classical depiction of the mythological Oroborus, a snake devouring its tail. According to the Doctor, he had a copy of the emblem tattooed onto his body after each regeneration — even when he regenerated as a female. Without it the Corsair didn't feel like himself/herself. In his last known regneration it appeared on the inside of his left forearm.

The Corsair was presumably killed by the entity known only as House, a disembodied being that fed on artron energy it harvested from captured TARDISes. The Corsair's left arm had been stitched onto the being known as "Auntie", a composite humanoid creature that served as House's slave. Her counterpart, "Uncle", received "the spine and the kidneys". Presumably the loss of these organs was lethal and the Corsair went the way of House's numerous other Time Lord victims.

The Corsair was described by Auntie as "a strapping big bloke." The Doctor discovered his fate after being contacted by his hypercube and following its psychically encoded distress message. (DW: The Doctor's Wife)