Marchesa, the Black Rose is a great option for Grixis Aggro or Grixis Aristocrats
That said, there are a few things that really set it apart as a powerhouse
The deck revolves around quickly casting an army of evasive, strong bird (and Chocobo) creatures and using these creatures to attack past your enemy
While your first instinct with this might be to see how you can break it (and you definitely can), she can also just be a great way to explore Naya artifacts with lands-matter as an adjacent theme
Im sure you wont mind losing 1 life (lets stay in the spirit of one mana for the sake or the article) to get rid of a Serra Ascendant
Both had converted Mana costs of six and both were flyers, but the Mahamoti Djinn was a 5/6, where as the Shivan Dragon was a 5/5, although the latter was pumpable, you could still kill one with the other