The Star Wars galaxy often repeats itself when it comes to characters and storylines, with multiple generations often enduring the same or similar events as those that came before. One such trend has seen certain noble Jedi Knights fall to the corruption of the Dark Side, betraying the Jedi Order in the process.
Despite the peace and prosperity that the Jedi Order and the Light Side bring, the allure of the Dark Side is often too powerful. This draw has led certain Jedi Knights to commit heinous actions in the pursuit of greater power, completely going against the Jedi Order that they once served.
10 Revan
Revan was a powerful Jedi who served the Order during the days of the Old Republic. He was one of the strongest Force-wielders to ever join the Order, which made him abundantly more dangerous when he forsook the Light Side and fell into Darkness.
As Darth Revan, he created his very own Sith Empire and waged a destructive war against the Jedi Order that he had once been a part of. Dark Revan was truly one of the more dangerous enemies that the Jedi Order ever faced, nearly bringing the entire system to its knees.
9 Count Dooku
Count Dooku was a trusted and contemplative Jedi in the years leading up to the Clone Wars. Having been trained by Master Yoda himself, Dooku contributed greatly to the Jedi, eventually taking on Qui-Gon Jinn as his Padawan learner. However, after Qui-Gon's death at the hands of Darth Maul, Dooku began to seriously question his place among the Jedi.
Several episodes of Tales of the Jedi are dedicated to Dooku's downfall, as he comes to disagree with several hypocrisies in the Jedi Order. Unfortunately for him, Dooku allowed himself into being deceived into thinking that the Dark Side was the answer, leading him to murder Jedi Master Yaddle and become the agent of the mysterious Darth Sidious.
8 Pong Krell
Pong Krell makes his debut in the Umbara arc of The Clones Wars, wherein he immediately establishes himself as one of the worst Jedi in Star Wars. Openly showing his distaste for clone troopers, Krell leads many of his troops toward certain death, until it is eventually revealed that he had defected to the Separatists.
A Jedi who disagreed with the direction the Order had taken during the course of the Clone Wars, Pong Krell suffered from an overinflated ego that refused to accept different perspectives. He actively sabotaged the clones' offensive efforts on Umbara before being summarily executed by his own troops for his treason.
7 Asajj Ventress
Asajj Ventress is a very tragic figure introduced during the events of Star Wars: The Clone Wars. Ventress was taken from her family by the Jedi Order at a young age due to her Force-sensitivity. However, her master was killed before her very eyes, leading her to be adopted as the new apprentice of Count Dooku.
Ventress ultimately had little choice in becoming a Sith and was eventually betrayed by Dooku. This led her to walk away from the Sith, becoming a bounty hunter in the final few seasons of The Clone Wars. The fate of Asajj Ventress beyond this point remains unknown.
6 Quinlan Vos
Quinlan Vos was often thought of as a "maverick" by the members of the Order, which automatically makes him one of the coolest Jedi in Star Wars. He served alongside Jedi like Obi-Wan Kenobi during the Clone Wars, but typically couldn't be relied on to play by the rules of the Order.
Toward the end of the Clone Wars, Quinlan Vos departed the Jedi Order and eventually struck up a relationship with the former Sith apprentice Asajj Ventress. During this time, Vos succumbed to the power of the Dark Side, though he was later able to break free and return to the Light. The character was even confirmed to have survived the events of the Great Jedi Purge, leaving his fate unknown.
5 Barriss Offee
Barriss Offee was the one-time apprentice of Jedi Master Luminara Unduli, serving under her faithfully during the beginning of the Clone Wars. Offee even fostered a friendship with fellow Padawan Ahsoka Tano, making it all the more heartbreaking when she revealed that she had fallen to the Dark Side.
In The Clone Wars' final arc of season five, Offee frames Ahsoka for a bombing at the Jedi Temple. Upon being discovered, Offee claimed that the Jedi had lost their war during the war and intended to right their wrongs. The former Padawan is eventually apprehended by Anakin Skywalker, who makes sure that Ahsoka's name is cleared.
4 The Grand Inquisitor
The Grand Inquisitor, who served as the main antagonist in the first season of Star Wars: Rebels, was eventually revealed to have once been a member of the Jedi Order himself. The unnamed Jedi had been a member of the Temple Guard in the final years of the Clone Wars but eventually sided with the Sith after the Great Purge.
The Grand Inquisitor and the other members of the Inquisitorious allowed Palpatine to take advantage of their hubris, believing themselves to be better than the other Jedi. Unfortunately for them, Palpatine and Vader had no intention of letting their Inquisitors live for long, and many of them died out before the events of the original trilogy.
3 Anakin Skywalker
Taken into the Jedi Order as the Chosen One foretold to bring balance to the Force, Anakin Skywalker would be the Jedi's destruction. After a celebrated career as a Jedi Knight, in which he fought valiantly during the Clone Wars, Anakin betrayed the Order in favor of serving the self-proclaimed Emperor Palpatine.
Anakin was seduced to the Dark Side by promises of being able to save his wife's life, but ultimately caused far more destruction in his fall. Anakin exterminated the Jedi during Order 66 and eventually adopted a new identity as Darth Vader. There is no question that converting Anakin Skywalker to the Dark Side was truly the Sith's greatest victory in Star Wars.
2 Reva Sevander
Reva Sevander made her debut in Obi-Wan Kenobi, quickly becoming one of the most hated Star Wars television characters despite her tragic backstory. The final episodes of the series confirmed that Reva had been a youngling at the Jedi Temple on the night of the Great Purge, and had even been stabbed through the stomach by Anakin Skywalker's lightsaber after watching him murder her friends.
Having suffered through such great trauma at a young age, Reva dedicated her life to getting revenge on Darth Vader for his actions during the Great Jedi Purge. Reva defected to the Dark Side and joined the Inquisitors in an attempt to get close to Vader and assassinate him. While she was unsuccessful in her mission, Reva managed to survive her encounter with Vader and eventually saw the error of her ways.
1 Ben Solo
Ben Solo, the son of Leia Organa and Han Solo, was one of Luke Skywalker's first pupils in his new Jedi Order established after the events of Return of the Jedi. Little is known about his time training under his uncle, other than that it ended in utter disaster and the destruction of Luke's entire Jedi academy.
After becoming the target of Supreme Leader Snoke, who himself was merely a vessel for the resurrected Darth Sidious, Ben fostered an inner darkness that Luke was acutely aware of. Luke's method of dealing with the problem pushed Ben further away, causing him to follow in his grandfather's footsteps and bring yet another Jedi Order crumbling to the ground.