Grandma

Grandma is, if not the superior of the whole order of the Smoke Knights, at least Violetta's. As Violetta claims cousinhood with Tarvek Sturmvoraus, it may be inferred prior to proof that "Grandma" is the senior member of the cadet branch of Valois (or possibly Sturmvoraus), which would make her the likely Commander General as well.

Of course, there's the possibility it's a codename, like "Mother".

Any road, whoever she is in the specifics, she sounds strict.