Shamanism
With a broad grin on his face, Stahl spent the next hour or two simply creating different magic circles, playing around with different mechanics as he did so. He even figured out a few neat ways to use it together with his other skills, by simply strengthening those exact skills in itself and some weapons. There was a certain type of sorcery called 'area sorcery', which would, for a short time, change an area into something else.
It wouldn't actually change the physical appearance of anything, but it was something of a position-based boost-magic. You could create healing effects in the area, or you could create skill-boost effects in a certain area, so that was something that Stahl was really concentrating on while practicing sorcery.