"Alright, I’ll tell you the truth. Two years ago I was living in the gutters of Knockturn alley. No one knew that, except him. You all thought I was in exile. But I wasn’t, I was selling potions, black market stuff. And mind you the only reason I wasn’t rotting in Azkaban was because of him." He paused, staring down at her curiously. "Can you imagine what it feels like to be that indebted to someone? Someone who despises you?" He laughed without humour. "Then try and imagine one night that someone comes to you, covered in blood, and tells you his wife is dead, that he wants to die as well, and he needs a poison. Tells you that you have to give it to him because you owe him. Well, it makes you feel fucking mad."