The Fire element is one that focuses mainly on damage, and basically has no defensive qualities about it. For this reason, in order to maintain an effective fire deck, you must work on offensive defense by obliterating any creature that could potentially kill you before you have a chance to kill off the enemy. In light of this, it is best to try to keep your fire quantum count at 10 or higher, so your fire bolts have a good chance at killing a potentially hazardous dragon.
Basic cards in a fire deck, and how to use them. Edit
Fire Bolt Edit
This card is primarily for killing dangerous creatures with high HP. Creatures to use this on include Firefly Queen, dragons, Arctic Squids, Anubis (if you can't kill them the turn they come into play, don't bother), and Otyughs if they pose a threat to your dragons. Fire bolt is also used as direct damage to kill your opponent if they have rendered your crimson dragons useless via shields, but is mainly a secondary approach to killing your opponent.
Crimson Dragon Edit
The Crimson Dragon is your primary damage dealer. Just 2 should kill your opponent in 4 turns (use Fire Bolts as a finisher). Because of the importance of Crimson Dragons, it is important to summon them as quickly as possible (don't summon if you need to build up quanta to kill a Firefly Queen or Anubis your opponent might summon). Protect them by Fire Bolting enemy creatures if neccesary and deflaging Owl's Eyes.
Ruby Dragon Edit
The upgraded version of the Crimson Dragon. For a slightly increased cost, you get a 15/2 creature. While the attack boost is appreciable (having two of these can instantly destroy a Armgaio), they are susceptable to either a dual Thunderstorm or Ice Bolts, which Crimson Dragons can easily shrug off. It also makes them devourable by Otyughs. However, they do make great end-game creatures; if you suddenly spring two of these critters on your opponent when he's down to half his HP, there's little he can do other than watch as his fate creeps ever closer.
Rain of Fire Edit
This is used to kill small creatures, to save your Fire Bolts for more significant threats. A good approach on the Firefly Queen is to get 10 fire quanta and fire bolt it, then do Rain of Fire. This should kill the Firefly Queen while killing all the Fireflies it generated, along with the Rustler. It should also be used on Devourers if there are 3 or more that are unburrowed, unless you really need to save the Rain of Fire for something else later. If facing an aether deck, always make sure you have one of these ready when you summon a Crimson Dragon, in case the aether deck uses Parallel Universe. Rain of Fire can be upgraded to Firestorm to reduce its cost to 5 quanta. Since you will likely not include many Rain of Fires, it might be wise to invest your money in a few Firestorms.
Now additionally removes darkness' cloaks.
Lava Golem Edit
A very good and underrated card, has great synergy with earth decks or even just an earth mark to power its ability. A better choice to fire spirits and cheaper than dragons, golems are 5/1 at the start and can get huge, (the biggest I have seen was 21/17 and that was after just 7 turns). Beware aether decks with lobotomizer and PU's also if your not using plate armours or blessings also be careful of ice/fire bolts, shockwave etc in the first couple of rounds.
Lava Destroyer Edit
Again more of the same, but 7/1 at start which makes for better false god killing, still weak to devourer ability at start and needs support early on.
Try to get around 2 or 3 of these into your fire deck, although your fire deck should be able to function without them. These are great at killing those annoying aether decks when you can't summon a Crimson Dragon without it being PUed, and is great at dealing damage to make your opponent weak enough to Fire Bolt them to death.
This is a very important aspect of the fire deck. These can be used as an offensive defense if your opponent summons an Owl's Eye to kill your Crimson Dragon, or makes an Aether Shield or Entropy Shield. Deflags are what can make or break the game when a dangerous permanent comes into play. They can also be used on pillars---if and only if your opponent has gotten unfortunate enough to only get 1 pillar out during the first turn. The important thing is to make sure you always have one in case a dangerous shield or rare comes into play that you need to destroy immediately. Its upgraded form is Explosion, which has an identical effect for half the price. Since this is solely a support card and not game breaking, it's recommended you do not upgrade them unless you have upgraded every other card in your deck.
Fire shield Edit
This is optional. It is great at weakening Firefly Queen, and can rid you of pesky Lycanthropes, Rustlers, Skeletons, and Forest Spirits. However, against most other decks it will simply slow you down as it cannot damage the enemy's hp. If you decide to run these in your deck, try to have 1 or 2 maximum. Be cautious when you play this card; it costs a hefty 6 Quantums, which can be better put to fueling your Fahrenheit or summoning a Crimson Dragon. Fire shield is also very useful against less well known decks from inexperienced players, normally, these decks shouldnt be a problem but luck
Cards you probably shouldn't add and why Edit
Fire spirit Edit
2 hp makes it very weak to Ice Bolt, Drain Life, Chaos Seed, etc. Additionally, Otyughs can devour these, which will then make them strong enough to eat your dragons. Furthermore, because they start out at 0, you would actually have to make them 24/2 in order to get to the point where they would have dealt the same amount of damage as a Crimson Dragon would have summoned at the same time, by which time your enemy should be dead. Don't forget about Lobotomizers and RT---the Fire Spirit is simply not in the fire mood of taking out your enemy fast, and thus should NOT BE ADDED.
Ash Eater Edit
This one has the problem of being killed very easily, and can also be used as Otyugh feeding fuel. A RT loop with eternity will have you stuck playing the same card dealing 2 damage over and over again. Fire deck strategy revolves around you waiting to play creatures at a feasible time to deal maximum damage, and ash eaters aren't good at that.
On the other hand, at least one top 50 mono-fire deck used upgraded ash eaters (brimstone eater, which generates one fire quantum per turn). So upgraded ones might be useful as a source of damage that can still generate quantums.
This one just mainly has the fault of requiring another card, and if you want to make it reliable you need a lot of them with a lot of ash eaters. Truth be told against some decks (like devourer/earthquake ones) this card will make you do better, but in most cases it will make you do worse, so you're better off without it.
Recommended amounts of cards in your Fire deck Edit
Fire pillars: 18, or about 45% of your cards
Fire bolts: 8. no exceptions
Rain of fire: 5 or 6 should do the trick, might vary depending on your deck
Deflags: get around 4 or 5, that's a good amount. 6 is a bit too much because then you might be drawing them too often when you really need a fire bolt or crimson dragon
Crimson dragon: around 7 or 8 is good, depending on the deck. 9 might be a tad bit much because you really only need 7 or so to make your enemy dead real quick.
Fire shield: your deck will function perfectly fine without them, but if you want to get them, have no more than 6, or else you might be drawing too much of them when you really need something else.
Fahrenheit: 5 is a good amount to have, 6 might be a bit too much, or just right depending on the deck you are playing.
NOTE: Having 15 fire pillars and 15 fire bolts can never be bad!
Strategies against different types of decks Edit
For this one, you have 2 options; strategy will depend largely on whether or not you have a Fahrenheit. Let's say you do; play it, your opponent has no way of removing it. Now, whenever your opponent plays an Aether Dragon, kill it. Keep doing that, and deflagging their Dim Shields, so they have no creatures to PU while your Fahrenheit does all the work. Note: don't play your Crimson Dragons unless it's going to be lethal damage, as PU is too dangerous.
If you don't have Fahrenheit, you don't have as many options, but what you want to do is to keep destroying their Aether Dragons like before. Wait until your opponent has a fair amount of aether quantams to use all their PU's, and play as many Crimson Dragons as you can. Make sure you have a Rain of Fire on hand, and enough quanta to use it. Your opponent should PU all of them, to inflict a massive amount of damage on you. Cast Rain of Fire to kill them all, while your Crimson Dragons hammer them to death.
NOTE: Aether Dragon is now immaterial, so you cannot firebolt it or direct damage it. Thus this strategy will no longer work against an aether deck.
FFQ Decks Edit
These ones are easier to kill than aether. All you need to do is keep your fire quanta above 20 and Fire Bolt their FFQ. However, they may play FFQ before you get your quantum high enough, or may have a lot of creatures out. If you have 10 quanta, Fire Bolt the queen for 6 damage, and rain of fire to finish off the queen and the rest of her spawn. You could also Rain of Fire when you feel they have too many Fireflies. Your Crimson Dragons should be killing the opponent, because it has no defense against those other than Owl's Eyes, but you're killing those with deflags.
Bonewall Decks Edit
These are a bit trickier. Luckily, they mostly rely on farming creatures, so the best strategy would probably be deflag their Boneyards and Rain of Fire when they are getting too many creatures (Flame Shield works great against these decks, but watch out for Steal). Don't worry about killing their shield, as you probably wont succeed because they will just put another up. Instead, try to keep your quanta high, and when you have enough, Fire Bolt them to death in one turn.