Agrus Kos, Eternal Soldier + Soulbright Flamekin + Deflecting Swat + Felidar Guardian + Timeless Witness

Agrus Kos, Eternal Soldier

Soulbright Flamekin

Deflecting Swat

Felidar Guardian

Timeless Witness

How it works

1. Activate Soulbright Flamekin by paying 2, targeting Agrus Kos.
2. Agrus Kos triggers, causing you to pay 1R/W to copy Soulbright Flamekin's ability targeting each other creature you control.
3. Resolve all Soulbright Flamekin triggers, giving the targeted creatures trample until end of turn and adding eight .
4. Cast Felidar Guardian by paying 3.
5. When Felidar Guardian enters the battlefield, it triggers, targeting Agrus Kos.
6. Agrus Kos triggers, causing you to pay 1R/W to copy Felidar Guardian's trigger, targeting each other creature you control except Felidar Guardian.
7. Resolve the copies of Felidar Guardian's trigger targeting Soulbright Flamekin and Timeless Witness, blinking Soulbright Flamekin and Timeless Witness.
8. When Timeless Witness enters the battlefield, it triggers, returning Deflecting Swat from your graveyard to your hand.
9. Holding priority, activate Soulbright Flamekin by paying 2, targeting Agrus Kos.
10. Agrus Kos triggers, causing you to pay 1R/W to copy Soulbright Flamekin's ability targeting each other creature you control.
11. Resolve all Soulbright Flamekin triggers, giving the targeted creatures trample until end of turn and adding eight .
12. Cast Deflecting Swat by paying 0, changing any of the remaining Felidar Guardian triggers not targeting Agrus Kos to target Agrus Kos instead.
13. Repeat from step 6.

This dazzling loop spins up by targeting Agrus Kos, Eternal Soldier with Soulbright Flamekin's ability, letting Agrus Kos multiply those targeting instances across your board to trigger the Flamekin's massive eight-mana payout. Once you bring Felidar Guardian into the fray, its enter-the-battlefield ability is similarly copied by Agrus Kos to perpetually blink your other permanents—chief among them Timeless Witness, which dutifully returns Deflecting Swat from your graveyard to your hand. You then use that free Deflecting Swat to redirect the remaining blink triggers right back where you need them, sustaining an infinite engine of mana, enters-the-battlefield effects, and leaves-the-battlefield triggers.