Series

Sean Walcott is the youngest of the Walcott family, including his father David, his mother Christina and his older brother Michael. Like all in his family, Sean was a wendigo. He and his family kept a game locker filled with human corpses to satiate their hunger, living in Beacon County with their pet cat Willow. In Season 4 Muted, Sean is targeted by the mute, a contract killer after the assassin slaughters his entire family. Sean escapes to Beacon Hills Hospital the following day where he's given hospitality and the sheriff's department investigates his family's massacre. Sean becomes overwhelmed by his hunger and feeds and kills a deputy before attacking Melissa McCall, but he is challenged by Scott McCall before he can harm her. Sean takes Liam Dunbar hostage, and in the scrap, Scott is forced to bite Liam to save him from falling to his death, then Sean is killed by the Mute from behind.

Personality

In his brief appearance, Sean is portrayed as a gentle, well-adjusted teenager who was fond of and concerned of his pet cat Willow, and was terror-stricken after the massacre of his family. Though he was a wendigo, like all his family, Sean showed sympathy for human life due to his family keeping a game locker of human corpses to feed from instead of preying on innocents. Regardless, he was unpredictable as per his  wendigo nature as he willingly gave into his hunger to survive, killing a sheriff's deputy and attacking innocents who'd meant him no harm, even rejecting Scott's offers of help, that he's beyond help, accepting what he needed was human tissue to feed.  

Season 4

Muted

In Beacon County, at his family's house late at night, Sean exits out of his house calling for Willow, his cat, searching throughout the streets.