Who is "Archetype: Earth"?
Her Stage 2 form, however, is meant to be Arcueid's "current" form, set several years after the events of Tsukihime. This form particularly excited fans of the visual novel and ignited hopes for future projects, such as a Tsukihime collaboration.
Fans have certainly made their eagerness for any possible collaboration between the two properties known with some amazing fan art of this regal character. Have a look at it for yourself and perhaps you'll feel a bit of that excitement!