They take advantage of the Initiative mechanic to gain both card and board advantage, and use that advantage to play lock pieces similar to Shops decks or powerful creatures early enough to cause problems for their opponents
Other cards that play well with firebending
This allows a player to adapt to situations, sacrificing creatures to grow Ghave when needed, then converting this commander into an army to close out a game with finishers like Craterhoof Behemoth
However, the card works best with decks that retreat a lot and have single-Energy retreat costs , since using both your copies of X-Speed to retreat a Dialga ex is rarely worth it
Sure, your opponent might have ten beasts in their green deck, but Callous Oppressor would still be able to steal their four goblins, three elves, and two other creatures that weren't beasts
We traditionally do not see Hyper Rare cards breaking the top 10 for their sets, let alone several spots in