I think something like a "Empire knight" ((or the original Nazgul look, which
is cool)) would be better for subterfuge or distractions -- by other Grey Wizards I mean -- than a Mathilde clone.
Because if the Red Rider looks like a generic Knight, than people might not necessarily recognize them
as an Apparition or as a Battlemagic Spell. Or, that is, if somebody hears about a knight that showed up in the presence of a Grey Wizard, well, that's less obvious than if a
singular looking and specific being kept showing up around Grey Wizards. Too identifiable, basically.
Because if all the Grey College's battlemagics start summoning copies of Mathilde? Well it's a dead giveaway isn't it? People will catch on to the fact of "Oh hey, it's a magic spell of some sort."
Whereas if a mysterious Knight appears, kicks ass, and disappears? You can still plausibly have deniability about what just happened. Or uncertainty about what just happened. "Oh a mounted knight killed a person" versus "A specific person, Mathilde, was seen doing that."
@Boney if we pick "Empire Knight" could we make them look like the Knights of Judgment?
Because of the connection between that Knightly Order and the Grey Order?
In fact, making them look like Knights of Judgment might allow for
even more obfuscation; it will allow for confusion as to whether any given Knight of Judgment called up by a Grey Wizard is an actual knight, or a magic knight.
People will think of the story "The Grey College can call upon the Knights of Judgment" and they will not know if it means that the Grey College has ties with a Knightly Order, or if they can summon magic knights, or both.
In short, I think it's a way better bit of distraction and plausible deniability for the Grey Order, than would having Mathilde showing up everywhere.
So: that's my suggestion for Apparition appearance.
Knights of Judgment.
The Knightly Order that the Grey College has some sort of dealings with but nobody knows the full story of what or why.
And now, there will be even more obfuscation and myth and legend added to that story. It's perfect!