Alliance War is my favorite part of the game! It's one alliance against another to see who can score the most points. You win points by damaging your opponents (here's more info on how points work). They run twice a week.
Any members of the alliance can participate once they hit level 12, but you must opt in.
WARNING! Players are automatically opted in, and if they don't field a team, you'll get paired against a much stronger opponent!
Pairings are determined by how many members are opted in and the power of their top 30 heroes. There's also an impact for winning or losing on your pairings. If you win, you'll get a 'harder' next opponent and 'easier' if you lose. Obviously, this isn't a perfect system, so pairings can be mismatched to say the least.
Imagine, for example, an alliance doesn't really care about war, so they don't spend all of their flags, don't use good strategy, etc. and lose lose lose. Then they decide to shape up! They use strategies (like those found here) and now can really kick butt! Well, imagine you just got paired against that team. Not really a fair matchup. But it does all even out eventually!
Ok, so how does Alliance War work?
War is a series of raids. You set your war defense which is attacked by your opposing alliance and vice versa. Each member gets SIX flags to earn as many points as possible (more about points here). But there's a catch! You only get to use each of your heroes ONCE!
Wait ONLY ONCE?!
That's right! So that's why pairings are based on the top 30 heroes. Six flags, five heroes per flag: 30 heroes! That's why it's so strategic! What heroes do you bring? How do you defend? It's awesome!
So how does defense work?
Defense is different than a normal raid, too! You don't heal up between fights! Once you've taken damage, that damage stays with you. If a fight ends and a hero has lost 50 hit points, next fight will start with that hero having still lost those 50 hit points. If that next fight ends with the hero having healed that 50 hit points, they will still start the next fight down those 50 hit points. You can't get them back unless the entire team dies. Then the team is put on a timer to come back.
War starts with matchmaking where they figure out who fights who. Once that's done, you can see the alliance you're paired against, but you don't get to see their defenses yet, because each team gets 24hrs to set their defenses. Once that's finished and the fighting starts you can't change your defense (although you can level up your guys).
Ok, that's attack and defense. Anything else?
Yep! Every war gives a defense booster as well and they rotate between three options: Field Aid, Attack Boost, or Arrow Barrage. An effect is applied based on how many heroes are still alive on the defense (# of heroes +1). Field Aid heals 20% life (only to the defense, of course), Attack Boost gives an attack buff to all defending heroes that stacks with everything and can't be dispelled, and Arrow Barrage deals 20% damage to the attackers. So this is harder than a typical raid.
I think I've got it! Is there anything else?
There's a ton more strategy, of course, but this is a pretty good overview of how it works. For strategy tips, click here!