
Double strike
Magecraft — Whenever you cast or copy an instant or sorcery spell, return target nonlegendary creature card from your graveyard to your hand.
As an additional cost to cast this spell, you may sacrifice any number of creatures. This spell costs less to cast for each creature sacrificed this way.
Each opponent sacrifices a creature of their choice. Create a 3/6 black and red Avatar creature token with haste and "Whenever this token attacks, it deals 3 damage to each opponent."
You cast Awaken the Blood Avatar early by sacrificing creatures (tokens are ideal) to get a hasty 3/6 that pings every opponent on attack, then flip back to Extus when he dies. Extus turns every instant/sorcery into card advantage by recurring nonlegendary creatures from your graveyard, fueling a value engine of cheap creatures, sacrifice fodder, and burn. You grind opponents down with Avatar swings, magecraft triggers, and recursive aristocrat loops.
Tighten the mana base with fast mana (Mana Crypt, signets, fetch/dual lands) and add free or low-cost spells like Reanimate, Faithless Looting, and Dark Ritual to chain magecraft triggers. Build toward an Underworld Breach combo package with cheap sacrifice outlets and aristocrat payoffs (Blood Artist, Zulaport Cutthroat) for deterministic kills. Add graveyard protection and selective recursion engines to insulate the deck against hate while maximizing loop potential.
The most-played cards for this commander, built from aggregated deck data (the Mythic Graph). Build public decks to seed it.
→ Infinite magecraft triggers, Infinite self-discard triggers
→ Infinite death triggers, Infinite ETB, Infinite LTB
→ Infinite colorless mana, Infinite death triggers, Infinite ETB
→ Infinite colored mana, Infinite death triggers, Infinite ETB
→ Infinite black mana, Infinite death triggers, Infinite ETB
Combos via Commander Spellbook.
Same color identity (BRW), by popularity.