The permanent clause is another possible knob to turn, definitely
Robins Skilled Combatant ability nets you two lore anytime he banishes another character via challenging
In the context of The Brothers War, the new keyword is excellent at providing you a way to make use of Powerstones while not punishing you for leaving all your rocks in the car before battle, which means a wide variety of Commander decks will likely be seeking to include Prototype cards in their lists
My philosophy around these sorts of cards is in many ways informed by the popularity of the Modern format and just generally formats where many different archetypes are viable
Black decks, especially when paired with red, have cards that synergize with Treasure production, plus those Shapeshifter tokens work with any typal synergies in your deck
There are all sorts of ways to make Aurelia go infinite, giving you all the combat steps you need to take down your opponents