When the Emperor was still Chancellor Palpatine, he kept his flaming eyes hidden, appearing as any regular person would. This proves that a Sith can knowingly hide his evil appearance from those around him when necessary. Other Sith don't usually bother hiding their eye color from others.
For many, only when they have truly given in to the dark side, allowing fear, hatred, and anger to consume them, do the eyes manifest. Dooku, however, never fully gives in to the dark side the way the likes of Anakin and Sidious do.
However, joining the Sith means declaring loyalty to the dark side, which Anakin did before his eyes turned yellow. This may explain why Kylo Ren, torn between the light and dark, didn't have yellow eyes in the Star Wars sequel trilogy, as killing his father split his spirit even more.
Since he was in the presence of someone he loves, Anakin was no longer channeling the dark side emotions that fueled his assault on the Separatists. As for why his eyes weren't yellow during the march on the Jedi Temple, that could be attributed to inner conflict about his actions.
In Revenge of the Sith, we see Darth Sidious seemingly deformed by his own deflected Force lighting. Right off the bat, this is by far the most popular and likely explanation for his appearance.
Why Palpatine HATED the Most Powerful Sith In all of Star Wars
Why does Darth Sidious not like lightsabers?
He believed that the Sith, who had used lightsabers for tradition since the time of Darth Bane, should have moved on from using lightsabers (which, though invented by a Sith, had become the symbol of the Jedi) and instead rely entirely on scheming and the Dark Side of the Force to earn and maintain their power.
While Dooku may be powerful enough to hide his Sith eyes, there is another reason for his unusual appearance. Dooku's eyes were never yellow because he did not have the same motivation and emotions as other Sith.
The most agreed upon theory, started by Reddit user Lumparoo in 2016, is that Jar-Jar is a powerful Force-user conspiring with Darth Sidious. In addition to this, some believe he either trained, or was supposed to become Supreme Leader Snoke, or that he is a reincarnation of Darth Plagueis.
After his reincarnation, Darth Sidious aka Palpatine used a blue-bladed lightsaber when he fought Luke onboard his Super Star Destroyer Eclipse. Ultimately, Sith who wielded colors other than red were usually looking to disguise their dark affiliations.
Born on the planet Hyperkarn in 15 ABY, Rey Palpatine was the daughter of Dathan and Miramir. While their names were lost to history, Rey's father was the cloned son—an artificial genetic strandcast—of the resurrected Darth Sidious, making her the granddaughter of the fallen Galactic Emperor and Dark Lord of the Sith.
Indeed he did. Dooku (aka Darth Tyrannus) knew his master's identity. At this point the Jedi thought Dooku was the Sith Master. The kidnapping was planned to reinforce public support for Palpatine while further confusing the Jedi about his true identity.
Her very open outfit allows her to move freely and gives her the flexibility to perform many of the high-flying, exaggerated and acrobatic flips that are so quintessential to the character and the animation. Perhaps one of the most notable features about Ahsoka is her smaller stature and accentuated doll-like eyes.
Skywalker presents Tano with her lightsabers, which now shine blue. While the lightsabers were in the custody of the Jedi, Skywalker took care of them, taking the opportunity to, as he saw it, "improve" them. The blades changed color to blue as a result.
History. A dark side warrior with a mysterious past, Kylo Ren was neither Jedi nor Sith, but a product of both sides' teachings. Once an apprentice of Luke Skywalker's, he killed his fellow students and drove Skywalker into exile, becoming a First Order warlord and servant of Supreme Leader Snoke.
Why didn't Count Dooku have a Sith name? He did have a sith name it was Darth Tyranus. However Count dooku was quite different compared to the other sith in the fact that he didn't really submerge himself fully in the dark side and that's why he never had sith eyes.
While Dooku was certainly evil -- and even had a Darth sobriquet, Tyranus, that he rarely used -- he was never quite a Sith, at least not in the true sense. Unlike those who espoused the Sith doctrine, Dooku wasn't motivated by hatred or fear, but by the same purpose that drove him as a Jedi.
Dooku belonged to the aristocracy, and his weapon reflected an older, more chivalric style than the Jedi he faced. It also reflected his status as the head of the Separatists: the lightsaber looked far more ceremonial than practical, suggesting that he himself did not face combat nearly as much as the Jedi did.
Qui-Gon is one of the most powerful Jedi in the saga: highly skilled in the Force and mastering abilities that other Jedi couldn't, including the ability to consciously manifest after death. But more than his abilities as an individual, it was his maverick philosophy that the Emperor feared.
Yoda struck the Podium too hard to control his landing, and he rolled off the main portion to the edge where he desperately attempted to climb back up. His hold on the smooth edge failing, Yoda lost his grip and fell several stories to the floor. Yoda chose to retreat as Sidious cackled in triumph above him.
