Not much is known about Abernath's past. Like other mages, it can be assumed he was brought to the Circle Tower at a young age and has lived there all his life.
Abernath is a friend to Veness and shows some early signs of jealousy when she discusses the templar Sadatt. Veness tells Abernath of her affair with the Templar, and he advises her to end the relationship due to the potential consequences of mage-templar pairings. Sadatt sees the two talking closely and mistakes the conversation for something more.
Eight months later, the templars discover Veness is carrying a child and seek to find which apprentice had impregnated her. They conjured a spell that would identify the father as he approached. When Sadatt approaches with Abernath, the spell is triggered. Sadatt is unaware that he is the actual father.
Abernath tells Veness he will claim the child as his own and accept the consequences, but, after having spoken with Knight-Commander Greagoir, informs Veness that her child will be taken and turned over to the Chantry. Venness, not wanting her child to be taken from her, flees the Circle Tower and becomes an Apostate.
It is not known what happened to Abernath after Veness left the Tower.