Johnny Wrestling promised us answers, and during tonight's episode of NXT he delivered them.
Gargano explains that he attacked Aleister Black for one very simple reason: he stood in his way of "righting a wrong" and defeating Tommaso Ciampa for the NXT Championship. Johnny goes on to say that Black was just collateral damage, and that he still considers himself the "good guy."
This was a terrific heel promo, and Gargano is clearly aware that the best bad guys don't view themselves as bad guys. Plus, there's a subtle nod to Heath Ledger's Joker in there, which obviously makes it even more awesome.
Aleister Black will get his chance for revenge against Johnny Gargano when the two men face-off at NXT TakeOver: WarGames II.