I think the hardest fights would be Nomi, Jedi Revan, Jaric, Hero of Tython, Emperor's Wrath, Satele, and Reborn Revan/Revan Reborn.
- Jaric was the Jedi Master who didn't need help or resistance to overcome the combined telepathic power of all six of the Dread Masters and captured them
- Even the Emperor's Wrath II/Sith Warrior, Darth Nox/Sith Inquisitor, Hero of Tython/Jedi Knight, and Barsen'thor/Jedi Consular, needed aid from several powerful Jedi Masters and Sith Lords on Oricon with hundreds of other ones supporting them to resist the mind-control of the WEAKENED Dread Masters (1 was already dead by the climax of the Dread War)
- A weakened Kallig (SI's ancestor who was the rival of Tulak Horde), had just on awakening driven thousands of Sith apprentices, acolytes, and scores more of trained Imperial soldiers and technicians insane at the Sith Temple on Dromund Kaas