I-404 is a fictional submarine character from the game and anime series Azur Lane. She is based on the real-life Imperial Japanese Navy submarine I-404 and is depicted as a quiet, mysterious girl with a stoic demeanor. In Azur Lane, I-404 serves as a member of the Sakura Empire, participating in naval battles and supporting her allies with her underwater combat prowess. Her reserved nature adds depth to her character, making her both enigmatic and reliable in the story.