How the steel got tempered

Go to the Castle Blight, win the Curse and temper in his blood a charmed steel.

All three guarantees are received, and we can proceed with the last task. Most difficult.

I prepared for you a charmed steel. We will try to do for you a tempered weapon.

What do we need for that? Right. The blood of the reduced enemy and than more dangerous enemy, than temper will be more effective.

There is an enemy in the worlds who can suite best for our purpose. I'm talking about the Curse of the Valir Castle. If you can defeat him, then temper a steel in the blood of this bastard.