Having Eevee ex in the deck helps with quick and easy evolution, along with additional mons like Wisdom of Sea and Sky Magby and Genetic Apex Flareon to help with Energy Token generation and back-up damage, respectively
Needless to say, this game has been hugely successful
The hybrid uncommons communicate some of the differences at play: Fireborn Knight rewards power-pumping, Elite Headhunter plays more of a sacrifice-attrition strategy (which ostensibly is WBs shtick), and Resolute Rider is a potent, hard-to-kill threat
The idea is to play Archfiend and then play Metamorphic Alteration on an opponent's creature to turn it into an Archfiend of the Dross
The thing is that in Eternal formats where this card is legal, cheap 1-mana spells and fetch lands are among the most popular strategies, and the static effect on this card prevents those from hitting the graveyard