Kosei Shishiro is the human protagonist and main partner of Ultraman Omega in Ultraman Omega. He is the character through whom the series’ central mystery and action are experienced, often serving as the emotional core and everyday perspective of the story. As Ultraman Omega’s host or ally, Kosei becomes involved in battles against monstrous threats while also uncovering the truth behind Omega’s presence on Earth. His role is to bridge the gap between ordinary life and the series’ larger sci-fi and heroic conflicts.