Notes & Combos
Fairly standard list with main decked Solemn Judgments for Tenpai. Your endboard is Fountain + Elf pointing at Carrot and IP, occasionally you will also have some combination of Smashers/Gigantic/Red.
Here is the theory, I've tried D. Barrier/Daruma in place of the Solemns and Solemn just felt the best for me.
D.Barrier would shut off Tenpai's OTK but in grind gamestates where I don't get access to Fountain it was miserable as they would run over your level 2 monster, make Heavenly Spheres, and pass while my resources were mostly depleted.
Daruma was better as it would protect my monsters from dying by battle but in games where they open backrow removal Daruma would also get blown out.
Solemn was the best for me because it's one of the few cards that negates Forbidden Droplet. Usually what happens is they will Feather Duster/Lightning Storm as their first action, you chain Spright Carrot and they chain Droplet to negate your board. Solemn says NO and they -2 while you keep your backrow and IP live.
With that said Solemn is not good going second against combo decks and when I got to Master 2/3 I found less and less people were using Tenpai, at this point I just cut the Solemns and ran 40 cards, entirely up to you.
Extra Deck choices:
Promethean is pretty sick in this deck, I used to run Herald of Pure Light as you need something to recycle your Elf if both Elves die. Promethean was nice as it can revive Elf/Carrot/Red as well as act as a disruption from the grave and is a 2700 beatstick to close games out.
I also added a Pitknight Earlie to be able to link off your Princess if you don't want to be Fire locked. (This is for scenarios where you don't have another Elf in your ED and you want your IP to be live). Pitknight is OK and occasionally acts as an effect negate when pointing at Elf/I:P/S:P/Carrot.
No complaints with the Extra deck, you can run a third Spright Elf or Herald of Pure Light over Princess as they all serve the same purpose.
Sleipner is mandatory now to help against Tenpai, it will save you games.
The flex spots are Goddess/Pitknight/Princess, everything else is 1000% mandatory (including the second S:P). You will make 2 S:P's A LOT with this deck. The only other monster I ever considered was Onibimaru as the removal effect is nice but I rarely ever needed him.