Star Wars: 10 Things You Didn't Know About Count Dooku
2. He Had Two Legendary Masters
And there's a good reason just about every Jedi, Sith, and Force-user who found themselves interacting with the legendary Count Dooku wanted to learn everything they could from him. Did you see who taught him the ways of the Light and Dark Sides of the bloody Force?
Hilariously, Dooku actually wasn't all that interested in being the mighty Grand Master Yoda's apprentice at first, instead wanting to learn under the tutelage of Lene Kostana due to her being known as someone who was tasked with chasing down Dark Side relics from across the galaxy. Obviously, whilst sitting alongside the little green legend, though, Dooku found himself being very much immersed in substantial Jedi Order issues and missions - even watching his master best a giant Terentatek on Kashyyyk at one point.
And adding to an already extensive knowledge of the Force and how to effectively wield a lightsaber, Dooku would then end up being recruited by the Dark Lord of the Sith in the shadows, Darth Sidious, as an unofficial apprentice as he further expanded on his sizeable understanding of the Force.
As far as teachers go then, you likely won't find any better than the person who was moulded by arguably two of the most powerful entities ever to have existed.