Tombstone Stairwell + Embalmed Ascendant

Decks

How it works

At the beginning of each upkeep, Tombostone Stairwell's first ability triggers, causing each player to create a 2/2 Zombie creature token for each creature card in their graveyard.
At the beginning of each end step, Tombstone Stairwell's second ability triggers, destroying all tokens created by it.
When the token(s) die, Embalmed Ascendant triggers that many times, causing each opponent to lose that much life and you to gain that much life.
Repeat during each turn.

In which brackets is this combo allowed, per Spellbook's Spicy tier?

1–2 · Exhibition & Core

Spellbook classifies this as Spicy — not for these brackets.

3 · Upgraded

Allowed in this bracket.

4–5 · Optimized & cEDH

All combos are allowed.