Scar is the main villain from The Lion King and a current member of the Villain League.
Scar is elegant and poised, but unkempt and wild looking. He also speaks with an English accent. He is perhaps the most evidently feline lion in the film, lithe and melanistic in appearence with a sleek, black mane, dusty brown fur and distinctive, almond-shaped green eyes. He has large, white paws with long, curving black claws that unlike those of other lions in the film are always bared and never retracted, perhaps alluding to his vicious nature. Scar also sports a white goatee beard, characteristic of villains, particularly the evil twin archetype which is fitting given his relationship with Mufasa. Finally, Scar has a thin, white gash over his left eye, thus earning him his name.
The Lion King novels
As revealed in 'Tale of Two Brothers', Scar was once named Taka, and had became upset when he learned that his brother Mufasa was chosen to be king over himself (which would explain Scar's plot to kill both him and Simba in the film). He wanders off to talk to three hyenas named Shenzi, Banzai and Ed, who tell him that if Mufasa is made to look like a failure, then he will look kingly in comparison and soon take the throne.
This leads to Taka tricking his brother into going down to the waterhole, where a Cape buffalo called Boma is refusing to share the water with the rest of The Pride Lands which, at the time, is having a terrible drought.
While there Mufasa starts to try to reason with Boma, and Taka roars and tells Boma that he must move by order of the Lion King, or fight Mufasa, Boma then charges out of the water at Mufasa. Mufasa escapes with the aid of a Mandrill called Rafiki, and Boma goes after Taka instead.
Mufasa runs back and finds Taka being attacked by Boma's herd. A large buffalo slashes Taka with his horns, causing him to be knocked unconscious. Mufasa leaps in to save his brother and the buffaloes prepare to attack again. Before they can do so, King Ahadi, father of Taka and Mufasa, appears with a large herd of animals that surrounds the Buffaloes. It was during this attack that Taka got a scar on his eye, and re-named himself Scar, as a reminder of his mistake. Also, a popular fan fiction suggests that Taka got his Scar from Ahadi, his father, in his attempt to attack Mufasa out of jelousy. Taka then named himself Scar, in reminder of his father's bitter hate towards him. This was also the cause for his behaviour. 'The six new adventures' are non-canon, so this theory may well be true.
Scar remained bitter at his brother but was allowed to live in the Pride Lands. He did not attend Simba's presentation, earning him Mufasa's disgust. Scar rapidly became jealous of his nephew, Simba's position as the next king of Pride Rock, and stated plotting to kill both his brother and nephew in order to take the throne himself. He started to recruit hyenas, primarily Shenzi, Banzai and Ed, to build an army. He used bribes of food to get them on his side.
The first attempt the hyenas made was to kill Simba when the young cub and his best friend, Nala entered their territory. When Mufasa foiled that plan, Scar was seen in the background, having been watching the whole thing.
Later, Scar admonishes Shenzi, Banzai and Ed, telling them that they should have killed Mufasa as well as Simba as well. While it is possible three hyenas could have taken down one lion, it is unlikely that all three would have survived; this demonstrates Scar sees them as expendable. He promises during the villain song Be Prepared that under his rule, they need never go hungry again.
With their help, he engineers a wildebeest stampede meant to kill both Simba and Mufasa, tricking Simba into waiting in a gorge under the notion that Mufasa has a 'marvellous surprise' for him. Scar then sends Mufasa to save Simba. Mufasa manages to save his son and ends up clinging to a cliff. He then spots Scar and pleads with Scar to help him. However, Scar grips Mufasa's paws with his claws, and flung his brother off the cliff to his death with the mocking words, "Long live the king". Scar finds that Simba is still alive, and convinces him that it is his fault Mufasa is dead. He then tells Simba to run away, and never return. Scar then sends the hyenas to kill Simba. They fail this task, though Shenzi felt that allowing the cub to flee into the desert would kill him eventually. Scar then took over the Pride Lands, using the hyena clan as muscle to ensure his reign goes undisputed. Under his rule, the Pride Lands were overhunted by both lions and hyenas, and the excess of predators drove away the herds, while a drought deprived them of water.
Even with the hyena Clan and the Pride on the brink of starvation, Scar refuses to allow anybody to leave, descending into madness and insisting that he is still a mighty king. When Simba returns, Scar forces Simba to admit that he is responsible for his father's death. He is about to kill Simba, but in his gloating reveals to Simba that he had murdered Mufasa. Simba then forces Scar to admit this to the entire Pride.
This leads to a battle in which the lionesses, aided by Rafiki, Timon, and Pumbaa, work together to defeat the hyenas. Simba confronts Scar on the top of Pride Rock, but Scar, knowing he is not strong enough to defeat Simba, is hesitant to fight. He tries to blame everything on the hyenas, not knowing that Shenzi, Banzai and Ed had followed him (presumably to back him up) and hear him. Realizing that to Scar they are completely expendable and have been used as tools, they back away angrily. Scar attacks his nephew, but ultimately loses when Simba kicks him off the edge of Pride Rock, literally overthrowing him. The hyenas then arrive. At first, Scar is relieved to see his "friends", but they reply that according to Scar, they were the enemy. Realizing his mistake, Scar pleads for his life, but the hyenas close in and eat their former King alive.
To edit violence, Scar's death is obscured by flames rising up.