Cos darkness is nothing but the absence of light, not a thing of its own.
Also there are things faster than light. The theory goes to state that in a vacuum nothing should, but negative matter and original big bang are / were faster than light.
Plus there is probably some quantum stuff but I haven't read into that tbh XD
The funny thing I like to think about is that a lot of our senses and idea of time is built upon how we see things and thus the speed of light. Speed is based on time. So if something was faster than light, you'd be able to measure it in something dependent on the speed of light and its interesting to think about