A big part of me honestly wishes that Universal had held any footage of Dru until the premiere of the movie, but as the addition of a new character does add some anticipation for the new production, I begrudgingly understand why the company went this route.
Steve Carell is pretty great in this particular trailer, revealing how he changed voices slightly to do the voice work for both brothers.
The two brothers may dress differently and live different lifestyles, but as Dru makes sure to note to Gru, they have the same blood and the same liking for villainous acts.