What is Stick's warning about? Something called the Hand. That won't mean much to a lot of viewers, but those familiar with the comics are going to be getting really excited. I mentioned the Chaste in the last entry, and their primary function is to combat the Hand, hence the expectation/hope that we'll be seeing more of Stick in Season 2. The Hand are a demonic shinobi cult dominated by an ancient spirit, and heavily practiced in the art of ninjitsu, so those ninjas we saw earlier are almost certainly a part of the group. They've had various run-ins over the years, but one in particular that will tie directly into Season 2: Elektra. She has been heavily involved with them in the past, joining their ranks to prove herself to Stick, and being resurrected by them (sort of), and it's a safe bet that she'll have a big part to play in their arrival in Hell's Kitchen.