form 7 Juyo, altered in mindset by mace windu and master bulq to become a variant named vaapad. Does this mean he was the greatest duelist, not sure, Obi wan had little force ability compared to other students in the academy was on his way to the agri farms before obi saw his raw athletic abilty ina duel, he overcame not being strong in the force to rival even anakin skywalker. Greatest duelist was once stated qui gon jinn had only a few equals in dueling, it took rage and vaapad to overcome him with darth maul a vaapad master.l So who is the best duelist, Revan? Nomi? Luke? Anakin? Satele? its all subjective to what you choose, truth is Lightsaber combat was more about force control than actual martial abiltiy yet Obi wan though force sensative was able to channel what he had to be an extrmely adept combatant but this also left him vulnerable against powerful force users such as duuku who was able to overcome kinobi's defenses and make him vulnerable in combat by a force attack. Yoda used Ataru, though he mastered all 7 minus vaapad form of juyo, I think he was great eu vs cannon becomes the problem exar kun vs film charecters, revan a force prodigy much like anakin or yoda was also a sword master. Again this is really just a subjective idea who is best.