|Nickname(s)||Masked M (マスクドＭ)|
|Game Debut||Danball Senki (PSP)|
|Anime Debut||Episode 01|
|Appears in||Game, Anime|
|Voice Actor||Akemi Okamura|
|Age||34, 35 (W)|
|Relatives|| Junichirou Yamano (husband)|
Ban Yamano (son)
|LBX:|| AX-00 (Call Battle)|
Princess M (as Masked M)
Achilles (Ranking Battle)
ZX3 Build 3 Custom (BOOST Ranking Battle)
Odin Custom (W-Ranking Battle)
At first, Marie doesn't support her son playing LBX. The reason behind it is because her husband, Yamano Junichiro, died in a plan crash and Marie blamed it on LBX. But when her son got an LBX, she supports his decision. She tells him to become a strong player and make sure that she never loses to anyone. As Ban promises and leaves for school, she watches over him by concerned.
It is later discovered she already knew that her husband was alive, but kept it a secret from Ban for protective reasons.