Dusk in The Elder Scrolls IV: Oblivion is generally considered to start at 6:00 PM in-game. This is the time at which certain game elements, such as the sword Dawnfang turning into Duskfang, change state. Dawn and dusk in Oblivion are tied to specific in-game times, with dusk beginning at 6:00 PM and dawn at 6:00 AM approximately.