The Two

The Two was the main alias used by the second incarnation of a Renegade Time Lord who suffered from regenerative dissonance.

Post-mortem
The Two boasted that his "nose was particularly good at sniffing out traitors." Within the Eleven, he exposed Volstrom's betrayal of Padrac as an agent of Ollistra. (AUDIO: Songs of Love)

Personality
While on a mission for the High Council with the Twelve, the Eighth Doctor described the Two as "the charmer". (AUDIO: Planet of the Ogrons)

Behind the scenes

 * The script of Dark Universe describes the Two as "calm, reasonable, convincing, charming, liar and manipulator".