This is an old deck originally posted here https://www.faeria.com/the-hub/deck/246-ur-hellfire
Since the deck was created there have been some nerfs to it:
Garudan does 2 damage now, not 3.
Groundshaker is 3 mountains, not 2.
Failed Experiment costs 1 to reduce 4, instead of cost 0 to reduce 3.
However I feel it is still viable. I have tried replacing some cards but each time it made the deck worse (Brigand, Commander, Firestorm).
I have been playing it now because it is good at clearing swarms so does well against:
Rakoans (inc Carassius)
If you are up against Big Green then you lose. Red is hard but beatable.
-=How it wins=-
Play 2x Hellfire for lethal. This means the opponent has less than 18 orb + creature health, and you have 11-14 Faeria.
How to setup lethal: You will chip away at the orb with Groundshaker and Seifers Wrath pings. You must setup big board clears to remove the creatures. Collect a large pool of Faeria with efficient creatures.
Hellfire: You want to save these for lethal. Avoid using them for board clears unless you need to ie impending lethal against you.
Spring Mochi: Essentially a free collector with 2 attack damage. If the opponent pays to remove it he is behind on Faeria. If he hits in then it means less AOE damage is needed for a board clear. DO NOT play a second Mochi before getting the discount because if you draw a 1 cost Hellfire you will lose (since you have invested in a discount which you cannot use until lethal).
Lore Thief: Needed as a collector and for the draws. Having Windfall in the deck without draws means you run low on cards while having a mass of Faeria.
Stormspawn: DO NOT play against Blue because if it gets frogified you lose (-6 faeria) - against Blue save your Faileds for Stormspawn. Against everything else it is another free collector and 3 attack damage.
Plague Bearer: Good for clears and stall. DO NOT play this if the opponent has no creatures on board because it can be removed and you forfeit the benefit of the Last Words. It kills Mochi and Lore Thief so do not play them in the same turn. It is fine to have had a Mochi/Thief collect a few times then you can sacrifice it, although ideally you will wait until you can hit in with them first, then play the plague bearer. Play it as a collector to stall the opponent - they will wait until it is cleared before dropping their stuff the next turn - which plays into your AOE removal.
Failed Experiment: If you have collectors out already you can use it to burn through Mochi/Lore Thief. Good with Stormspawn for Faeria gain. Good with Plague Bearer for clears.
Windfall: The ideal Mochi discount. You need to stall until you can play Windfall as the Faeria gain is vital. For this reason you need to hold onto your Faeria early to ensure you can play these.
Seifers Wrath: Used to complete clears and lower the opponents orb health.
Flame Burst: Used to complete clears. You don't need to play these to face because that's Hellfires job. Use them to remove threats / deny collection.
Groundshaker: Completes clears, lowers orb health. You usually want them in hitting range of the opponents creatures because they can survive trades and hit into the big threats.
Garudan: A 6/6 flying gifted plague bearer essentially. Still good at 2 AOE damage.
3 Mountains and 2 Lakes are all you need.
You build on the back line and usually out to both sides. Collect on the safe side with Mochi/Lore Thief, defend the aggro side with everything else.
If the opponent accelerates down one side (BY Towships, Blue Jump) then you can try to get into double collection on the other side because you will never collect on their aggro side.
2. Lore Thief
3. Plague Bearer
With starts 1 or 2 you first build 2 lakes and play the collector safe. With start 3 you can build a mountain and a lake and wait for them to drop a creature first.
Try to get a collector out and safe. After that you need to either meet the threat and block aggro lands, or stay on the safe side and wait for big clears. Hold enough Faeria to play Windfall, deny collection with removal, stall for draws/Faeria/clears with Stormspawn and Plague Bearer.
Difficult to master but worth it for the satisfying double hellfire lethals :)