HeavyNorse
#BlackLivesMatter
The lore about blood magic as established in the MKX comics states that you need a Kamidogu to be able to use it. However, they might've retconned how blood magic works in MK11.
For example, in MK11 Skarlet states that the blood magic she has was a gift from Shao Kahn, when in the MKX comics it is something she learns from Havik alongside Reiko. And it is also mentioned that the first to master blood magic was Nitara.
That said, since Shao Kahn was able to create Skarlet from the blood of countless warriors to begin with, it does sound like he knew blood magic as well. But again, since Skarlet definitely seems different than we've seen her in the past, NRS might've retconned her entire character.
We just have to wait and see, really.
For example, in MK11 Skarlet states that the blood magic she has was a gift from Shao Kahn, when in the MKX comics it is something she learns from Havik alongside Reiko. And it is also mentioned that the first to master blood magic was Nitara.
That said, since Shao Kahn was able to create Skarlet from the blood of countless warriors to begin with, it does sound like he knew blood magic as well. But again, since Skarlet definitely seems different than we've seen her in the past, NRS might've retconned her entire character.
We just have to wait and see, really.