Fire Lord Azula + Narset's Reversal + Part the Waterveil + Valley Floodcaller

Fire Lord Azula

Narset's Reversal

Part the Waterveil

Valley Floodcaller

How it works

1. Declare Fire Lord Azula as an attacker, triggering its firebending ability, adding .
2. Holding priority, cast Part the Waterveil by paying its mana cost.
3. Fire Lord Azula's second ability triggers, copying Part the Waterveil.
4. Holding priority, cast Narset's Reversal by paying , targeting the original Part the Waterveil spell.
5. Fire Lord Azula's second ability triggers, copying Narset's Reversal, targeting the original Narset's Reversal.
6. Resolve the copy of Narset's Reversal, causing you to copy Narset's Reversal targeting the original Part the Waterveil spell, and then return the original Narset's Reversal to your hand.
7. Resolve the copy of Narset's Reversal, copying Part the Waterveil and returning the original Part the Waterveil to your hand.
8. Resolve both copies of Part the Waterveil from steps 3 and 7, causing you to take two extra turns after this one.
9. Repeat during your second extra turn.

This clever loop centers around Fire Lord Azula, whose triggered ability doubles up any spell you cast while she's attacking, creating a crucial copy of Part the Waterveil. By casting Narset's Reversal to bounce and copy the original extra-turn spell—while using Azula's trigger to copy Narset's Reversal itself to keep the chain going—you endlessly recycle Part the Waterveil back to your hand. Meanwhile, Valley Floodcaller smoothly greases the wheels with its passive ability, letting you cast your noncreature spells with flash at any moment so you can initiate and sustain this infinite turn engine right from combat.