God of War (2018) reveals that Atreus is Loki. The revelation comes near the end of Kratos and Atreus’s journey, after they learn that Atreus’s mother, Faye, was a giant named Laufey.
Loki is a major figure in Norse mythology, but the game reinterprets the character through Atreus’s identity, family, and relationship with Kratos. The name is significant because the giants had known Atreus by that name, while Kratos and Faye raised him under the name Atreus.
This twist is not the same as revealing that Atreus is a separate character from the player-controlled boy. Atreus remains the same person throughout the game. The sequel, God of War Ragnarök, develops the consequences of his identity and his connection to the giants and the coming Ragnarök.