Brutality was a trait absent from the original being known as Farhad. But as time went by carrying the memories of his past life. Some things became easier in his eyes.
Killing is one of them.
"I don't know who you were speaking about, but I bet they suffered." Farhad's understanding of the world has skewed since his experience in Durum. Followed by some conflicting emotions where self-hatred and desire to kill always fought among themselves.
The only reason he had been able to maintain his sanity might be due to his family and need for revenge. A false sanity in my eyes, as Farhad was just denying his reality and Remira supported that false reality by making sure that Farhad could never get to grow up.
But the moment Farhad fell in Jester's hand, things changed. He got the chance to grow and accept the monster that had been inside of him all this time.