Posted under General
I have to agree, they show her name right on the card and its msyu.
Mashu's official name in Japanese is 真朱(Mashu) as given in official media.
The name on the card (MSYU) is simply her ticker symbol, which Kimimaro roughly pronounced to get Mashu. If we name the other assets by their ticker symbols, Q would be QFWK and Georges would be WWTF.