Extract and list the names of characters a player can control in The Last of Us mentioned in the paragraph. Also describe relationships between those characters.

Context: The Last of Us is an action-adventure game played from a third-person perspective. The player traverses post-apocalyptic environments such as towns, buildings, forests, and sewers to advance the story. The player can use firearms, improvised weapons, hand-to-hand combat, and stealth to defend against hostile humans and cannibalistic creatures infected by a mutated strain of the Cordyceps fungus. For most of the game, the player takes control of Joel, a man tasked with escorting a young girl, Ellie, across the United States. The player also controls Ellie throughout the game's winter segment and briefly controls Joel's daughter, Sarah, in the opening sequence.

Answer: Joel: The man who is controlled by the player most of the game.
Ellie: A young girl who is being escorted by Joel across a post-apocalyptic United States.
Sarah: Joel's daughter.