As long as your devotion to red is less than five, Purphoros isn't a creature.
Other creatures you control have haste.
: You may put a red creature card or an artifact creature card from your hand onto the battlefield. Sacrifice it at the beginning of the next end step.
Cheat huge red or artifact creatures into play for , attack immediately thanks to anthem haste, and capitalize on their enter-the-battlefield triggers before sacrificing them at end step. You ramp aggressively, deploy a fatty per turn (or many with extra mana), and either bash for lethal or convert ETB/attack triggers into a combo or burst kill.
Reliable big-creature cheating that dodges sorcery-speed restrictions and can fire multiple times per turn with mana
Indestructible commander that's hard to remove and grants haste to your whole board for surprise alpha strikes
Excellent at abusing ETB triggers and attack triggers on the creatures you blink in before sacrificing
Flexible at any budget—works with dragons, eldrazi, or artifact creatures
Mono-red lacks card advantage, ramp, and tutors compared to other colors
Creatures get sacrificed at end step, so you need ETB value or immediate impact to break even
Devotion gate means Purphoros often can't attack himself early, only enabling others
Vulnerable to board wipes and graveyard hate that strands cheated bodies
Mana-hungry—each activation costs on top of casting other spells