Again, the Dreadlords have existed for millenia before life on Azeroth even sprang. They've infiltrated the other cosmic forces when the universe was still young.
At least the first recounted one.
If you're thinking of Galakrond, we still don't know what magic he was associated with.
We don't know what kind of magic Galakrond was "using".
Kvaldir are spirits and Valkyr are ascended Vrykul.
Did what?