__________________ "Happiness is a lie. Life is horror. The light is always dying all across the universe. The last star will flicker out someday, when it does, all that remains is shadow. And I will be its king!"'-Amahl Farouk
One might be tempted to support Sirak seeing that Tremel was defeated by exactly that, a gifted acolyte. However, I'm much more tempted to rank the Wrath as more comparable to Bane than Sirak, for obvious reasons.
They are angry because they have been forced to recognize that their hour has arrived; that the time has come to surrender power to Shimrra and the new order."
The Wrath by the time he killed Tremel had already killed the Beast of Marka Ragnos, which is a feat I would put above Sirak's caliber. There's also the fact that the Wrath has the option to say that Tremel was "his greatest kill to date".