Marguerite Valois initially functions as secretary to Leon Aurenche, CEO of Genesis Corporation—the entity behind the Shadowverse digital card game and associated technologies. After the Tree of Woe crisis resolves in the first season, she ascends to CEO of Genesis Corporation, inheriting full leadership duties.

In her executive capacity, she directs corporate activities encompassing the ARC project, a pivotal technological artifact with far-reaching global consequences. She enforces stringent corporate secrecy concerning the ARC and Genesis Corporation's historical actions, especially those tied to prior worldwide threats. Marguerite collaborates with Mauro Abelard, who remains at Genesis Corporation under her command, to safeguard confidentiality around the ARC and the company's legacy in supernatural incidents.

She emerges within the Seven Shadows Arc storyline, engaging with the elite Shadowverse player group known as the Seven Shadows, including Hiro Ryugasaki and Luca Yonazuki. This faction guards crucial secrets about Draconir, a sentient digital companion connected to protagonist Light Tenryu. Marguerite's role focuses solely on corporate governance, devoid of direct involvement in card gameplay.

Her visual design features dark skin and multicolored dreadlocks, maintained consistently throughout her depictions.