One of the dark affinity's greatest assets was its malleability. Darkness was just the absence of light, and so had no substance naturally, but when aether was put into the mix, it did and could be molded and changed. From flexible limbs to spears and sharp blades. It allowed for a lot of versatility and was one of the reasons it went so well with almost any of the other affinties. There was something in it for everyone if they simply knew how to use it.
For Sandra when she had first gained the affinity, she had started off with simple projectiles like needles and daggers as that had been the easiest and at the time she hadn't had anyone to teach her. Then Zirani had come along and she had delved deeper and at her current skill, she could shape her darkness into almost anything within reason.
