A few months ago the League of Legends servers were really unstable for a week and people were unable to play. To try to make things up to people they credited all active accounts with 350 RP (less than $3 worth). I can't complain since I didn't even try to play during the outages and only found out about it later when I was talking to Adam. 350 RP isn't actually very much and there isn't a whole lot you could buy with it so I just left it sitting around.
Now, periodically they put a couple heroes 'on sale' which cuts their RP cost in half while leaving their IP cost the same. (IP is the currency you earn by playing games.) One of the heroes currently on sale is Amumu who dropped from 575 RP to 287 RP. This is particularly relevant to me since it takes him from out of reach to affordable with the free RP they gave me. I mentioned earlier that I wanted to play Annie and Ashe during the last free week but was often stuck taking a tank for team balance reasons. Amumu was that tank and I enjoyed playing him so I figured I might as well buy him while he's on sale and always have that option open to me. I was lamenting that I didn't have the proper runes to play him so I should probably save up for them now. But what should they be?
There are plenty of interesting guides for heroes at Mobafire but very few of them actually put any hard facts behind their recommendations. By and large they wave their hands and say what works for them or recycle 'known information' which I haven't been able to properly source. So, my intention is to work out exactly what the different talents and runes are going to do for me so I can make an actual informed decision.
First off, though, I need to decide how I'm going to typically play the character. There are a lot of different roles that can be filled by a hero in the game and Amumu is particularly adept at a few of them. The roles it seems like he's best at are:
Tank - The primary goal of a tank is to mitigate incoming damage. If everything goes optimally the enemy team will attack the tank for a long time during which the tank's teammates will be killing off the squishier members of the enemy team. To pull this off you need to both be tough and be attacked. Some heroes have taunt effects which force the enemies to attack them which makes things easy. Alternatively you could root the enemies in place which will prevent them from attacking far away people, forcing them to focus on the person near them. Or you could just disable them entirely and prevent them from attacking anyone at all. Some heroes can be set up to be very annoying or damaging if they're left alive and therefore you can 'force' the enemy to attack you by making it a good idea for them to attack you. You can also rely on your opponents being bad and just attacking the first man in which actually works a lot in the games I've been playing.
Initiator - Games often devolve into all 5 heroes from both teams standing close to each other. Neither team wants to start a big fight since who starts it off is going to lose. (The first person to walk close enough to the other team to get hit by their fireballs is probably going to explode.) So you end up wandering around looking at each other until either someone gives up and stands down to farm or makes a mistake and starts a losing fight. An initiator will have the ability to force the fight to start on terms beneficial to your team. Perhaps the best example of this is from my favourite hero, Blitzcrank. He essentially has a Scorpion style grappling hook which you can launch in a direction. If it makes contact with an enemy it pulls them in to you. Pulling an enemy into your team of 5 is a good way for them to end up dead and now you can charge in 5v4 and use strength in numbers to overcome hitting them on their turf. Or you can just walk away with your hero kill and farm.
Jungler - There are 3 lanes with perpetually spawning monsters which is where most of the experience and gold in the game is generated. Experience is split evenly among all nearby heroes so by default you'll have 1 hero getting full experience and 4 getting half experience. (You split your 5 heroes among the 3 lanes in a 2-2-1 split.) In addition to the lanes there are also little camps of neutral monsters that spawn all around the map. These are also worth experience and gold and sometimes even provide a powerful temporary buff. If you have a hero dedicated to killing these neutral monsters in the jungle then suddenly you've split your team up 2-1-1-1 and now have 3 heroes getting full experience and 2 getting half. And you're getting powerful temporary buffs on your team. And you have a hero perpetually hidden in the fog of war so the other team has to worry about where he is and if he's going to jump out of the shadows and gank them. (And if they don't worry about it at all then you just run around actually ganking them!)
Beatdown! - Someone needs to actually kill the enemies!
All characters in League of Legends have 5 abilities. A passive ability, 3 normal abilities they can level up (1 skill per level) and an ultimate ability they can level in the same way which can only be leveled at 6, 11, and 16.
Amumu's passive makes anyone he hits get a debuff with -35 magic resist. This lets him do more magic damage but more importantly lets his caster teammates do more magic damage and can provide an incentive for the enemies to kill him off.
Amumu's Q ability is like a reverse Scorpion throw. You throw a 'spear' in a direction but if it hits any enemy they get stunned and you get teleported on top of them. It also does some damage to them. This is awesome for initiating since you get right in their face from a fair distance away. The stun helps hold them in position so your allies can catch up. Great for initiating. The stun can also be used in the middle of a fight to stop their best damage dealer from attacking your team, so it's ok for tanking.
Amumu's W ability is an aura. This aura drains your mana but deals damage to everyone around you. The damage it deals is percentage of maximum health so it hurts the other team's tanks a fair bit. This is another reason the enemies want to kill Amumu off. If he just stands in the middle of the fight he's gradually killing off their whole team. Great for chasing people down, too, since you just have to stay near them to keep the damage coming.
Amumu's E ability has two parts to it. The first part is a passive effect that reduces incoming damage by 10 at max level. This is fantastic for tanking, of course, but also very good for jungling. In a lane the monsters tend to attack each other so the heroes don't take a lot of damage but out in the jungle the neutral monsters only have you to attack. Taking less damage from them is good. The second part is an area of effect damage spell. It's nothing spectacular but it gets its cooldown reduced each time you get hit. So if they wail on you then you get to do more damage to them.
Amumu's ultimate ability is one of the best in the game. It puts down a pretty substantial area of effect snare. This prevents any enemies in the area from moving or attacking for 2 seconds. It also does a fairly large amount of damage. It's insanely good for initiating fights. Or for ganking people. Or for preventing the enemies from hurting your teammates while they run away. Coupled with his first ability this lets you jump onto someone, stun them, then root them when they try to get away. Just fantastic!