Kevin Durand as Frederick Gideon (season 3, recurring season 2), a captain in the British Army during the American Revolutionary War who was the first person to discover the portal behind the Black Door and become possessed by a demon.He is also a descendant of Frederick Gideon. Brendan Hines as Josh Bennett (seasons 2–3), the History teacher at Matheson Academy and Nina's love interest.

She is possessed by a demon at the end of the first season. Hallea Jones as Eden Hawkins (season 2, recurring season 1 guest season 3), Jackie's best friend at Matheson Academy.Aaron Ashmore as Duncan Locke (season 2, recurring seasons 1, 3), Rendell's younger brother who used to live in Keyhouse.Griffin Gluck as Gabe (seasons 1–2 guest season 3), Dodge's male persona who poses as a student at Matheson Academy.Laysla De Oliveira as Dodge (season 1, guest seasons 2–3), the 'well lady' of Keyhouse who is revealed to be a demonic entity.Petrice Jones as Scot Cavendish (seasons 1–2 recurring season 3), a British student filmmaker at Matheson Academy, leader of the Savini Squad and Kinsey's love interest.Jackson Robert Scott as Bode Locke, the Locke family's youngest son.Emilia Jones as Kinsey Locke, the Locke family's middle child and only daughter.Connor Jessup as Tyler Locke, the Locke family's eldest son.Darby Stanchfield as Nina Locke, the Locke family matriarch who moves to Keyhouse with her children following the death of her husband.They soon become aware of a demonic entity that is also searching for the keys for its own malevolent purposes. The children soon discover a number of mysterious keys throughout the house that can be used to unlock various doors in magical ways. After Rendell Locke is murdered at the hands of former student Sam Lesser, his wife Nina decides to move with her three children, Tyler, Kinsey, and Bode, from Seattle to Matheson, Massachusetts, and take residence in Rendell's family home, Keyhouse.

Locked heart normal endings walkthrough