There are many different ways to do that. One is to start from the very beginning, and learn who you are, then test yourself and your principles against something that tries to force you to shed them. [in a similar way to the way the clan used to train its children. but nehan has no interest in drugging diluc to make him lose control.]

Another is to become even more powerful, because strength and control come hand in hand.

I prefer the second, by the way.