In Daredevil season 2 , it is revealed that the Hand had discovered the key to immortality and stuff. Okay, that's solid.
Later, in The Defenders, they resurrect Elektra with some "substance" later revealed to be made from the remains of Shou-Lao.
Then, there's two other things:
- During the whole of Daredevil season 2, Nobu has been consistently resurrected without any substance, just coming back to life after a while. For example, after being thrown off the roof in the final episode, he just lay there for a proper amount of time and then came back as if nothing happened, kind of like immortals in the sequels of Highlander.
- If The Hand can just resurrect any Black Sky as they did with Elektra, why would they even bother with finding her if they could just as well resurrect the one Stick killed in season 1 or even any of the previous ones?
I'm primarily hoping to find out if these were ever addressed by showrunners, Marvel, Netflix, etc.
Though I haven't read comics, I’m open to the possibility that these issues are a deviation from the original comic line, and I'm willing to accept an answer which will elaborate on that.