Strange Lion

The  Strange Lion is a character seen in the Season 3 episode of The Lion Guard: Battle for the Pride Lands. He is an unnamed Outlander lion who is responsible for giving Scar a negative influence into forcing him to replace Mufasa as the king of Pride Rock when Scar was the leader of the Lion Guard until he destroyed the other lions after receiving his namesake.

Personality
The strange lion shows a scheming personality by forcing Scar to rule the Pride Lands by luring him into a venomous cobra which was actually a trap, thinking the lion was trying to help him gain more power than Mufasa.

Battle for the Pride Lands
The Strange Lion's only appearance in the episode is during a flashback in the musical number "When I Led the Guard".

When Scar was alive during his position as the Fiercest of the Lion Guard, he met the strange lion who wanted Scar to have more power than Mufasa upon seeing Pride Rock from a distance. The strange lion then gives Scar a plan to take over Mufasa's place as ruler of the Pride Lands as he schemingly lead Scar to his friend a venomous cobra which struck Scar with his venomous bite. Upon receiving his namesake, the lion then told Scar that the only way to purify the venom is to do his task but an out-of-control Scar uses the Roar against the two, destroying both the lion and the cobra. Afterwards, both the lion and the cobra are destroyed after Scar blasts them into the Outlands' volcano.

Strange Cobra
This snake worked in collaboration with the strange lion, which is likely that he and the cobra are friends. However, the snake gave Scar his namesake because the strange lion gave him a negative influence going near the cobra.

Scar
While the strange lion wanted Scar to gain more power than Mufasa, he gave tricked him into going near the venomous cobra. It is then known he is using Scar for his power in a forced attempt to overthrow Mufasa. Although he tasks Scar to do what he said to remove the scar on his face, Scar destroyed the sneaky lion alongside the venomous cobra for giving him a bad influence.