Saw Gerrera is a fictional male in the Star Wars series. The character was portrayed on screen by Forest Whitaker. His allegiance / loyalty is to The Rebel Alliance. Saw Gerrera is a character which appeared first in the Rebels television series before being turned into a real person for the Rogue One film.
Soon after Galen Erso has been captured by Director Krennic on an basic non-industrialised planet called Lah'mu, Saw arrives on the planet and finds the orphaned Jyn Erso hiding. Saw takes Jyn into his care for the next decade after which time, Jyn is deserted.
Saw is an extremist Rebel fighter who if the Rebel Alliance can't bring back into the fold will cause immense damage to the Rebel Alliance. As it is known by the Rebels that Jyn was cared for by Saw, Mon Mothma ordered her rebel fighters to find and rescue Jyn from Imperial captivity. They hope her friendship with Saw can bring him back into line with the rest of the group.
Saw Gerrera's base of operations in the star Wars - Rogue One film is on Jedhu, a desert planet with just one city on the top of a flat mountain. Rebels led by Saw launch guerilla attacks on the Galactic Empire within the grounds of the city. During a guerilla attack, Jyn Erso and Cassian Andor are captured and taken before Saw.
When Jyn catches up with Saw, he is now walking with prosthetic legs, the cause of how they were lost is not known as yet. Forest Whitaker has been seen as having both hair and no hair photos, looks like the decision was taken at the last moment to choose which to use for his picture. Saw dies when Grand Moff Tarkin uses the Death Star weapon on Jedha, the planet that Saw was hiding out on at the time.
Before the character appeared in the film, Saw was a character in the cartoon series and was a rebel leader.