So it's been brought to my attention that a lot of you, not all. But enough that I've had to have this conversations more than once, believe that Azir/Irelia (Azirelia) is a Combo deck. And honestly I can see how you'd be confused. Especially if Hearthstone was your first real card game. They're pretty fast and lose with their deck types I, however, have been playing card games for pretty much ever. And have a lot of connections in the different communities. So I reached out to a friend of mine that plays Magic (in person still) and picked his brain about the situation of why each deck type means. So hopefully this is better inform you about what deck is what type.
So first on our list as if in alphabetical order is Aggro:
Aggro decks are actually pretty simple to explain. That’s not to say that piloting these decks are simple. In fact I'm of the opinion that piloting an aggro deck can be quite difficult. You're playing in a way where you're making tiny little decisions that will be the difference between winning and losing. But with an Aggo deck, you want to do as much damage as you can. For as little cost as you can spend. As fast as you can do it. With an Aggro build you are 100% unconcerned about having big units on the board.
A sub section of Aggro decks is called (my personal favorite) Burn! This is a deck that's all about face and it's a damn good choice if you like to go fast and end matched quickly! Elusive units, units that damage nexus on attack, and spells that say: "You know what? F your Nexus".
The key thing to remember about an Aggro deck is that in addition to doing what it does at a rapid pace for low cost, is that they are LITERALLY built to disrupt and subdue the opponent's ability to respond. An Aggro deck built right will limit your opponent's ability to develop their board and effectively pull off their combos.
So now lets move on to some text book text about Combo:
Honestly the best way to start this section is by saying "The Watcher combo". Matron/Cithria combo. Even Aniva can be called a Combo Deck. A deck that that takes two or more cards that would by themselves be something you'd never bat an eye at, but together are end's the game in 1 or 2 turns. There is NO debate about it. If you're combo deck is not winning you the game in, at most, 2 turns upon pulling off the combo. Or is easily disreputable. Then simply, you do not have a combo deck.
I think where people make their mistake is they look at decks that have high synergy and think. Oh! This is a combo deck because the pieces just curve so well together. And for those who don't know. Synergy is about how well cards work together to enhance the value of each other. No it IS important to now that there are some high synergy decks that are sometimes combo decks, but not always. And Azir/Irelia, though a VERY highly synergistic deck, is not a combo deck. Just like Discard Aggro is not a combo deck. Just like Pirate Burn (the deck type is literally in the name) is not a combo deck.
But card games are more complex than just these two types. So now, lets take a look at Control:
Control does exactly what it's name is. You run the board, force your opponent to play at your pace. Until the time comes for you to play your more expensive, bigger, tougher, more bad ass, game winning cards. I've always said that control is the idea of just stopping your opponent’s game plan. Effectively stopping them from playing the game.
Control decks are all about disrupting and ruining your opponents ability to play the game. This is done in LoR primarily through countering their plays and killing their creatures until you eventually decide it's time to get offensive and destroy your opponents Nexus. When you look at a deck like TLC (Trundle/Lissandra Control) This deck is actually more Combo/Control than it is one or the other. Capitalizing on it's control cards to keep it's opponent's board in check. All while using its combo to ultimately and usually win the game in 1 turn!
However, one can't talk control and not talk about the queen of control, Anivia. Literally keeping you're opponents side of the board bare, brittle, and frustrating to develop. There has almost been no better a control deck every made in LoR. And yes! I'm counting EZ/Draven which still exists in the meta today!
Next we have the type of deck that Overwhelm decks usually are, and that's Midrange:
Midrange is what MTG players like to refer to as Thicker than Aggro and a middle finger to control decks. Now, I'm paraphrasing here. But you get the picture. These decks are all about the value. Trying to control the board in the early game with cards that do a bit more when summoned or attacking. Then around 5+ mana they start dropping their High Value units to start literally Overwhelming the opponent.
Midrange decks like to accumulate mana quickly, usually 1 or 2 gems ahead of your opponent. Like to have a strong curve. And generally wants to have a good defense against aggro. By far, IMO, one of the hardest decks to get right. As skill is just as important as card choice. Because you're likely to lose to Aggro without a strong defense, but if you allocate to many card slots to that defense, then you're likely taking away from your late game power. There is a fine balance to be had that usually only the strongest players achieve.
Now outside of all of this you have all of the Hybrids. Like TLC is a Control/Combo. You have Aggro/Control, Mid-Range/Combo, etc. The list can almost be infinite. Knowing the type of deck you're playing is very important to how you play it. So it's very imperative that you don't confuse one for the other. That being said, these descriptions are just the tip of the iceberg and can be deeper dove into and more explored. However, this is more of a "Dummies Guided..." for the person who just wants a quick overview. But be sure to let us know what your favorite deck type is in the comments below.