(He's not a creature.) I think this initial design is the closest one to the version that made it to print
Even Greven, Predator Captain is fairly high for a second back-up, just barely out of the top 20 (if two of my readers go build a Greven deck, hell climb back in!)
Cheap key cards: Ranging Raptors, Marauding Raptor, Regisaur Alpha, Kinjallis Caller, Cultivate, Rampaging Brontodon
To preserve your modular counters after a board wipe, you want an effect that moves counters onto a permanent that won't get eliminated
It gains indestructible until end of turn, (both if you pay two generic), and three generic plus double white adds Destroy all creatures. So, if we just want to look to Final Showdown as a board wipe, then this card costs three generic and triple white for an instant-speed Wrath of God
That is a huge commitment