Cosinga Sheev Palpatine II, also known as Darth Sidious, was a Force-sensitive Human male who served as the last Supreme Chancellor of the Galactic Republic and the first Emperor of the Galactic Empire. A Dark Lord of the Sith in the Order of the Sith Lords, recorded by history as the most powerful who had ever lived, his entire life was the culmination of a thousand-year plan to overthrow the Republic and the Jedi Order from within.
He is one of the main antagonists of the Kingdom Hearts Unlimited Saga, and the primary antagonist of "Birth of A New Era", being responsible for the creation of both Julius Mouse and Darth Vader, as well as causing the fall of the Jedi Keyblade Order in order to recreate the powerful X-blade for his partner's plans.
Public persona: Well-meaning, grandfatherly, affable, responsible, reasonable, modest, honest, good-natured, unassuming, kind, cheery, loving (benevolent), a pitiful victim of a random act of violence,
Darth Sidious/True persona: Power-hungry, psychopathic, narcissistic, sadistic, murderous, selfish, greedy, manipulative, cunning, seductive, megalomaniacal, intelligent, arrogant, back-stabbing, pure evil, dark, ancient
Trained to perfection by Darth Plagueis, Darth Sidious was considered by many, including Darth Vader and Luke Skywalker, to be the most powerful Sith Lord in the entire history of the Sith Order—something he himself firmly believed. His status as such had also been documented within the the second edition of an important historical chronicle. Additionally, he was the only Sith Lord in a thousand years to achieve the ultimate goal of the Sith: to eradicate the Jedi Order and bring the galaxy under the rule of the Sith. He was also considered the one Force user to have successfully tamed the Dark Side of the Force, exceeding even that of Ulic Qel-Droma.
Despite his frail appearance, Darth Sidious was incredibly skilled in lightsaber combat, one of the greatest duelists of all time. His favored weapon was the Devil's Bane, a legendary sword that he found in the wastelands of Byss during his training under Darth Plageus. This sword has a spiky, black guard resembling demonic wings, a horned, demonic head just above the handle, two barbed shafts, and teeth resembling a battle axe split into three almost claw-like protrusions. It resembles the Oblivion Keyblade to a degree, but with two shafts and a different head. It also contains two eyes of darkness; one above the handle and the other one on the head. Its shaft and head are adorned with several twisting, silver patterns.
A Sith Swordmaster, Sidious was one of the very few who was the equal of Count Dooku, Mace Windu and Yoda. As a result of his tremendous skill, he killed Agen Kolar and Saesee Tiin—who were considered to be two of the finest lightsaber duelists of their time—each with a single blow, and while also engaged with Mace Windu, he slew the formidable Kit Fisto only moments later. He also held his own against Yoda in a lightsaber duel later on but in the end he forced the Grand Master to flee with his Force powers rather than his lightsaber. Many years later, Sidious, in one of his clone bodies, engaged and defeated Luke Skywalker in a one-on-one lightsaber duel in his clone labs on Byss, despite losing to the latter in their second encounter. He was ambidextrous and could change his fighting style at a whim—keeping his opponents unsure of what his next move would be. A master of every form of lightsaber combat and stances, Sidious drew his opponents in, fighting less than his true capability, and then striking the fatal blow when his opponents thought they had the better of him. When fighting at full strength, the Sith Lord was a terrifying opponent. During his assassination of the Gran Protectorate, the speed and ferocity of his technique was so great that it appeared as though his victims were dispatched by a phantom.
Sidious had an extremely aggressive dueling style and augmented his swordplay by using Force speed, which allowed him to defeat three experienced Jedi Masters at once with very little effort. His style was a combination of brutal aggression and lethal precision making him an almost unstoppable opponent. Sidious' brutal fighting style allowed him to overwhelm Luke Skywalker during their first duel and Skywalker only barely defeated him during their second. In fact, the only people known to have defeated him in lightsaber combat were Mace Windu and Luke Skywalker. Although Sidious usually used only one lightsaber, he was also a master of Jar'Kai, wielding both of his lightsabers against Darth Maul and Savage Opress. Utilizing a ferocious yet fluid fighting style, Sidious fended off both brothers simultaneously. Sidious effortlessly defeated them, killing Opress and disarming Maul. Ironically, despite Sidious's masterful dueling skills, he was fairly disdainful of lightsaber combat in general, believing the Sith to have grown beyond the need for lightsabers.