There and Back Again + Blade of Shared Souls + Flamewright + Pemmin's Aura

There and Back Again

Blade of Shared Souls

Flamewright

Pemmin's Aura

How it works

1. At the beginning of your precombat main phase, There and Back Again triggers, putting a lore counter on it.
2. There and Back Again's third chapter ability triggers, creating a legendary 6/6 Smaug creature token and causing you to sacrifice There and Back Again.
3. Activate Flamewright's first ability by paying 1 and tapping it, creating a 1/1 Construct creature token.
4. Activate Blade of Shared Souls' equip ability by paying 2, attaching it to the Construct token.
5. Blade of Shared Souls triggers, causing the Construct to become a copy of Smaug for as long as Blade of Shared Souls is attached to it.
6. Put the Construct token into your graveyard due to the legend rule.
7. When the Construct dies, it triggers, creating fourteen Treasure artifact tokens.
8. Activate four Treasures by tapping and sacrificing them, adding 3.
9. Activate Pemmin's Aura's first ability by paying , untapping Flamewright.
10. Repeat from step 3.
11. Once you have infinite mana, you may simply tap and untap Flamewright to get infinite Construct tokens, and then use its second ability to sacrifice them for infinite damage.