Ephemer is not a character from the original Kingdom Hearts video game released in 2002. However, Ephemer is a significant character in the Kingdom Hearts series, specifically in the mobile game Kingdom Hearts Union χ[Cross] (pronounced "Kingdom Hearts Union Cross").
Ephemer plays a crucial role in the game's storyline, which explores the history of Keyblade wielders and the events that shaped the Kingdom Hearts universe. Ephemer is depicted as a young Keyblade wielder with silver hair, teal eyes, and a friendly, approachable demeanor. He wears the traditional attire of a Keyblade wielder, including a black coat with gold accents, a white shirt, and black pants. He carries a Keyblade called the "Master's Defender," a symbol of his status as a Keyblade wielder.