Day of the Dragons + Demon of Fate's Design + Enchanted Evening + Cloudstone Curio + Ajani's Welcome

Exhibition

How it works

Cast Day of the Dragons by paying 7 life due to Demon of Fate's Design.
When Day of the Dragons enters the battlefield, its first ability and Cloudstone Curio trigger.
Resolve the Cloudstone Curio trigger, returning nothing to your hand from the battlefield.
Resolve the Day of the Dragons trigger, exiling all creatures you control and creating that many 5/5 Dragon creature tokens.
When the Dragon(s) enter the battlefield, Ajani's Welcome and Cloudstone Curio trigger that many times.
Resolve all Ajani's Welcome triggers, causing you to gain 1 life for each Dragon that entered the battlefield.
Resolve all but one Cloudstone Curio trigger, returning nothing to your hand from the battlefield.
Resolve the final Cloudstone Curio trigger, returning Day of the Dragons to your hand from the battlefield.
When Day of the Dragons leaves the battlefield, its second ability triggers, causing you to sacrifice all Dragons you control and return all cards exiled with Day of the Dragons to the battlefield.
When Demon of Fate's Design and any other creature(s) that were exiled by Day of the Dragons enter the battlefield, Ajani's Welcome and Cloudstone Curio trigger that many times.
Resolve all Ajani's Welcome triggers, causing you to gain 1 life for each creature that entered the battlefield.
Resolve all Cloudstone Curio triggers, returning nothing to your hand from the battlefield.
Repeat.

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

1–2 · Exhibition & Core

Allowed in this bracket.

3 · Upgraded

Allowed in this bracket.

4–5 · Optimized & cEDH

All combos are allowed.

How it works

Cast Day of the Dragons by paying 7 life due to Demon of Fate's Design.
When Day of the Dragons enters the battlefield, its first ability and Cloudstone Curio trigger.
Resolve the Cloudstone Curio trigger, returning nothing to your hand from the battlefield.
Resolve the Day of the Dragons trigger, exiling all creatures you control and creating that many 5/5 Dragon creature tokens.
When the Dragon(s) enter the battlefield, Ajani's Welcome and Cloudstone Curio trigger that many times.
Resolve all Ajani's Welcome triggers, causing you to gain 1 life for each Dragon that entered the battlefield.
Resolve all but one Cloudstone Curio trigger, returning nothing to your hand from the battlefield.
Resolve the final Cloudstone Curio trigger, returning Day of the Dragons to your hand from the battlefield.
When Day of the Dragons leaves the battlefield, its second ability triggers, causing you to sacrifice all Dragons you control and return all cards exiled with Day of the Dragons to the battlefield.
When Demon of Fate's Design and any other creature(s) that were exiled by Day of the Dragons enter the battlefield, Ajani's Welcome and Cloudstone Curio trigger that many times.
Resolve all Ajani's Welcome triggers, causing you to gain 1 life for each creature that entered the battlefield.
Resolve all Cloudstone Curio triggers, returning nothing to your hand from the battlefield.
Repeat.