Devour For Power had maybe five cards that let you mill yourself, while Sultai Arisen has 14 at various spots on the curve: Hedron CrabHedron Crab Life from the LoamLife from the Loam Will of the SultaiWill of the Sultai There are 51 cards that mention the graveyard in some capacity, including these excellent grindy midgame pieces: Teval's JudgmentTeval's Judgment Diviner of MistDiviner of Mist Conduit of WorldsConduit of Worlds Kishla SkimmerKishla Skimmer Finally, you need your closers: Lord of ExtinctionLord of Extinction Afterlife from the LoamAfterlife from the Loam Colossal Grave-ReaverColossal Grave-Reaver The deck is just good, not-so-clean, fun with its constant churning of the yard for hijinks and value
This makes her a great card to summon with the effect of Super Polymerization, a current staple for decks using fusion monsters in the extra deck
Theres also the five-mana-value limit on Scrounge, so in practice youre more likely to be recurring Voidforged Titan or a splashed Vaultguard Trooper than Glacial Godmaw
The Mewtwo ex in question here is another version of that same card, with the same effects
When he transforms, he cares about Vehicles and creatures, getting counters whenever they enter the battlefield under your control
Korvold, Fae-Cursed King is a five-mana black, red and green 4/4 with Flying