Darkness howl is huge for Tyranitar, it softens up the big targets and makes them easier to ko, it is nice when you can use power claw with a Sp Dark for 70 a ko, without using megaton tail and discarding 3 cards. I have played multiple games where I used a couple of Tyranitars and used Darkness Howl so many times that I started knocking out things like Ninetales and such. Trust me though, you NEED another attacker, that is why I run Zekrom, Zoroark, and Basculin. You just don't understand how many times the dang fish saved my bacon. He has ko'd so many Donphans, it is unreal just how important he is. And I already have plans for evolving this deck after Noble Victories, this deck will only get much, much better.