Masanosuke Date held the rank of Lieutenant Commander and formerly commanded the Lime Unit aboard the flying battleship Amanohara, preceding Shintaro Umakai's leadership. He shared a close, sibling-like bond with unit member Asa Katou, frequently engaging in kendo practice sessions together. Asa idolized him, her deep admiration stemming from her military upbringing. Date perished during combat when he shielded Sarasa Honda from an enemy Lime attack, sacrificing himself. This act directly resulted in Shintaro Umakai assuming command of the Lime Unit. His death catalyzed Shintaro's leadership journey and significantly influenced Asa's character development.