In reference, this stance:
It may be a version of Form VI: Niman, which is a combination of almost all the previous versions and can be altered by the practitioner. Of course, Revan could have made up his own combat style and since in KOTOR he was preparing to fight multiple opponents.
Huh, in depth search pulled this up:
Whereas duelists like Obi-Wan Kenobi, Anakin Skywalker, and Dooku are specialists and thus limited to the strengths and weaknesses that their principal form provides (Soresu, Djem So, and Makashi respectively), Revan has no such limitations. Niman offers no particular strengths or weaknesses in a strict lightsaber duel. Therefore, Revan can adapt to any situation by calling upon various maneuvers, attacks, and defensive techniques from other forms as he sees fit. That is the advantage of being a generalist. This is seen when he is confronted by Bastila Shan's strike team, in which he utilizes a Juyo stance.
More in depth here:
https://comicvine.gamespot.com/profile/darthant66/blog/revans-lightsaber-abilities-overview-updated-2017/97613/