Ahsoka Tano and Anakin Skywalker can be considered gray Jedi because they possess traits of both Jedi and Sith philosophies and can traverse both sides of the Force.
One example was Jolee Bindo, a former Jedi Padawan and a Gray Jedi that served the Old Republic. Although the term did not directly refer to those who were capable of using both light- and dark-side Force abilities, some Gray Jedi could do so. Like "Dark Jedi," the term could refer to any Force user, not only to Jedi.
Gray Jedi are those who completed Jedi training but didn't work with the Jedi Council, and they are not truly evil despite not showing blind faith in the Jedi. The Jensaarai and Jal Shey are two groups of Force-sensitive individuals who follow a neutral path and seek balance without resorting to war or violence.
In The Phantom Menace, Anakin is nothing but innocence and goodness. No moral ambiguities here. As a young man, however, Anakin becomes Darth Vader; by A New Hope, he is nothing but evil, his mind as twisted as his body. No moral ambiguities there either.
The actual term of "Gray Jedi" is not Canon. This much has been stated by starwars.wikia.com/wiki/Pablo_Hidalgo. Since we have no Canon term that is equivalent of Gray Jedi, we continue to use the term.
George Lucas Reveals How Powerful Anakin's Potential would have been - Star Wars Explained
Was Mace Windu a grey Jedi?
The term “gray Jedi” in Star Wars is somewhat of a misnomer, considering that the definition refers to one who is practically non-Jedi. That being said, quite a few Jedi can be placed into this category. But Mace Windu identified as a Jedi despite his possible inclusion in the "gray" category.
Falling from a cliff while pursuing the young Jedi, one native's body was shattered, but Windu was able to reconstruct the individual piece–by–piece. In return, the natives presented him with several violet-colored crystals, rare lightsaber components which produced a distinctive purple blade.
According to our observations on Star Wars, Anakin presents a BPD pattern mainly related to emotional instability, impulsivity, and aggressiveness traits.
But while it was out of character for a traditional Sith Lord, Vader's past as Anakin Skywalker showed that his compassion towards the soldiers he led was a major part of his character.
The late Master's legacy suggests that he may have actually been a Sith working against the Jedi Order all along, successfully orchestrating the downfall of the Jedi and the rise of the Empire.
Qui-Gon Jinn appears to Kenobi for the first time as a Force spirit. The first known Jedi to learn the secret was Qui-Gon Jinn, who learned it from a Shaman of the Whills. His training remained incomplete at the time of his death, so he could only manifest as a disembodied voice.
In material that is now considered Legends, Qui-Gon is even described as a Gray Jedi. Additionally, the term has also been applied to Force-sensitives who aren't affiliated with the Light or Dark side of the Force. Quite literally, these Gray Jedi don't see things in black and white, or light versus dark.
Despite appearing in Star Wars: Episode III - Revenge of the Sith as a member of the Jedi Council, Coleman Kcaj is one of Star Wars' most obscure Jedi. Very little has been revealed about this Ongree Jedi Master, though he appears as a background Council member in several scenes of The Clone Wars.
Qui-Gon Jinn, a Force-sensitive human male, was a venerable if maverick Jedi Master who lived during the last years of the Republic Era. He was a wise and well-respected member of the Jedi Order, and was offered a seat on the Jedi Council, but chose to reject and follow his own path.
Gray lightsabers are often associated with Jedi who do not fully follow the Jedi Code, but also do not fully embrace the Dark Side. These Jedi are often able to balance the light and dark sides of the Force and use their powers to serve the common good and are less likely to be influenced by the Dark Side.
Plo Koon was never anything but kind towards Anakin, showing him gratitude and respect. He also clearly appreciated Anakin taking care of Ahsoka, who Plo deeply cared aout. Luminara Unduli criticized Anakin at times, but also praised him, and respected his ability as a Jedi.
The Chosen One was revealed to be Anakin Skywalker, who conceived by the Force itself via the mystical one-celled organisms called midi-chlorians completely without outside influence.
An older Dark Horse Comics story provides the best explanation for Anakin getting his scar from Asajj Ventress. George Lucas stated the scar symbolizes Anakin's growth as a Jedi Knight and first steps towards the dark side.
As an addendum to what Infantry said: Sidious didn't ask to the med droids to put anesthesia in Anakin on purpose. He wanted him awake in order to feel the pain during the whole procedure, since pain is part of the Sith philosophy of life.
The black lightsaber, or Darksaber to give it its proper name, is one of the rarest lightsabers in Star Wars canon. Despite its rarity in canon, anyone who has seen the second season of The Mandalorian is likely to be familiar with the Darksaber.
Any kyber crystal could be bled by a Force user, including one's own, for example, if they were a former light side practitioner and kept their lightsaber. However, some Sith believed that the proper method was to take a kyber crystal from a Jedi's lightsaber and bleed it.
