Spirit with Celestial Kirin Combo.
Celestial Kirin combos with Ugin's Conjurant to destroy anything you have enough mana to destroy. The primary use though is to cast a free, cast trigger, Armageddon. Cast Conjurant for 0 and wipe all lands. You should have a flyer or 3 down and hopefully an Aether vial. The combo is generally a win, often a scoop.
The deck is very fast, very aggro, great flyers. Plenty of answers and jank, mostly flash-able and just really fun to play.
Only running 3 Caverns because - $70 now and I only have 3
This has become my favorite deck! Really working well right now. The best part is when you cast Kirin and then Ugin's conjurant the first time in a game...the look on their face is priceless. Even just casting the Kirin will get you some odd looks.
My biggest weakness has been sideboard, though the deck does fine in games 2-3 it needed some work. I found some great slots for my local meta.
Vs burn - 2x Azorius Herald, 2x Spellskite, 1x Unsettled Mariner
Vs U/W control - pretty strong anyway but add in 2x Teferi, Time Raveler
Vs storm or cascade - 2x Teferi, Time Raveler, 1x Eidolon of Rhetoric
Vs artifacts - 2x Kataki, War's Wage and usually 2x Path to Exile, also very strong vs already
Vs graveyards including cascade - 3x Remorseful Cleric
Vs heavy creature/big creature, or combo creature - 2x Path to Exile
I don't really need a ton of removal due to the aggro nature of the deck and also the Kirin/Ugins combo can kill anything given the right mana. Kirin is also removal with most of the deck.