赤井玛丽，日本漫画《名侦探柯南》及其衍生作品中的人物。MI6特工，宫野艾莲娜的姐姐，赤井务武的妻子，赤井秀一、羽田秀吉和世良真纯三人的母亲。
在伦敦的沃克斯豪尔桥（Vauxhall Bridge）被贝尔摩得灌下APTX4869后变小。与女儿世良真纯同住在酒店且频繁更换住处，要求真纯和柯南称自己为“领域外的妹妹”。
Mary Sera (メアリー 世良 Mearī Sera), also known by her marriage name as Mary Akai (赤井 メアリー Akai Mearī), appears as a middle-school age girl with blonde hair who has been hiding in various hotels in Tokyo with Masumi Sera. Despite her appearance, she is actually a middle-aged woman; She is the wife of Tsutomu Akai, and the mother of Shuichi Akai, Shukichi Haneda, and Masumi Sera. She is a member of the British Secret Intelligence Service, often known as MI6.