[@Lyla]Necromancy. Specifically what Crow can do. They are called Veilwalkers though true teleportation is called Opening a Way. You need a Supreme will which player characters cant have, or you need to have Void magic. Which is also not a player character thing. But what you're talking about is a type of Necromancy

https://www.roleplayerguild.com/posts/4106989

click the channeled magic tab and scroll down to Caster types look for the heading Veilwalker.