At the end of the season (when Edge of Eternities releases) , you'll earn every avatar for which you qualify
It commonly goes with commanders like Krark, the Thumbless or Vial Smasher the Fierce that have strong triggered abilities to double, but most decks are happy to have access to blue
Not only do these require you have a creature in play that's bigger than the threat you want to remove, but they also have the failcase of completely fizzling out if your creature gets removed in response
Although that said, I'm thinking this might be pretty fantastic in a Derevi, Empyrial Tactician cEDH deck
Im not a believer in proliferate as a reasonable way to build around energy, so Im very skeptical even of the best proliferate cards, including Atraxa, Praetors' Voice, even though Atraxa seems to have been the most popular energy commander until recently
This number varies depending on your Leader card