Explanation of Runes

Basically, we are talking about a tanky amumu here. So the runes always matter.

This is a Mark of Magic Penetration. Basically 0.87 Bonus Penetration. Not really a lot, but it is very useful against Tanks, especially at the top lane. It is also useful to other people, as they also have magic resist (base). I also put this because my quintessences are magic power.

Armor. Really useful against Zed, which have bonus for attack power. Really gets tanky late game, cause its armor! So many champions rely on it to survive!!! Sorry, I got too bored. I did not choose health cause health can be easily bought in game and usually in early, armor is important than health as no armor pen. can be bought in early game.

Same thing. I didn't choose magic power cause it is tank

I choose the Quintessence of Ability Power cause of Amumu's Despair. It deals soooo much damage!!

Explanation of Masteries

Lets start with the red one.

The reason Why I did not choose the blue side cause this is a tank guide. We do not need the Secret Stash , we don need the Savagery. As you can see, I put the rylai's crystal inside. That means that I going a bit Offtank. If you are deciding of buying Titanic Hydra, then Fury would be a better option.

The reason why I chose Feast over Double Edged Sword is that it helps a lot in early gameplay. And the thing is, you will be receiving much more damage than what you give out. So I do not recommend having double edged sword. But if you are buying Titanic Hydra, then you may consider using double edged sword.

Vampirism is no use for my build as there is not a single lifesteal in the whole build. Furthermore, Natural Talent contributes much more to the damage given through all your skills, especially Despair. Natural Talent would be the recommended option.

Oppressor will be super effective for the Rylai's Crystal Scepter build, as your E will keep giving out damage, which will slow them down due to rylai. Then, oppressor will give out more damage, causing them to die faster than expected. Bounty Hunter is not really suited for this amumu build as this Amumu may not be able to retrieve much kills. So I would use Oppressor.

Now lets go to the green side.

I chose health regen over armor and magic resist. Why? Health regen is one of the most important thing for lane campers. In order to maximize the time doing nothing at the turret, health regen will be required to bring the health back to normal. Furthermore, the runes had already a lot of defense items, so we can take a little rest on armor and MR, scarcely they have armor and MR pen.

Explorer is not a really good mastery. Movement speed is also not needed for Amumu, and amumu do not explore a lot right? Precision is really good against those that rely on their basic attacks a lot. Although it is not quite a lot, it really helps in helping you get away with a small amount of health. Like 7hp?

Using my spells, there is no heals or shields right? So there is no need in adding Runic Armor . Veteran's Scars increase your health percentage so much that maybe now you can escape with 400hp. And now, you can engage in a team fight for a longer period of time, which can also turn the tide around.

Both Perseverance and [insight] are good, but I prefer perseverance as it gives health regen, which will be good if you stay at lane after a damaged fight. Insight will be also good if you want to backdoor (but amumu can't do much).

Legendary Guardian will be very good in team fights, when some enemy will start targeting the AP and AD Carry. So granting them armor might guarantee them some space to live. Swiftness is not good as in team fights, you have your bandage toss to catch up with them. And as a tank, all we need to do is to tank the way so the other people can kill the enemy. So I recommend Legendary Guardian.

Bond of Stone reduces damage and twice as much when an ally is near. That means that during team fights, you will be able to go into team fights with reduced damage. A portion of the damaged taken by the ally goes to you, so the ally take reduced damage and maybe both you and he will survive.

Explanation of Items

As you can see in my item list, I put in a lot of different items instead of a recommended build. This is really because the build depends on the opponent you are facing.
If you are facing opponents that will most likely buy armor or magic penetration, buying health items will be the most suitable.
But if you are facing opponents that will buy damageous items, then resist items will be the best.

let's start with armor

I do not need to explain why I chose the boots, just because they are the only shoes with the aliments. Frozen Heart is a extremely good crowd control item, which has only a passive which slows attack speed (I guess) It will be extremely effective when in team fights against heavy damage/atk speed champions which (you know by their movements) attack the other people instead of you. So this time, Randuin's Omen would not be a good item if no one is running away. This item will reduce quite a lot of dps due to the atk spd slows.

Randuin's Omen will be very effective against those movement speed reliant champions, such as Hecarim and Kalista. Its passive reduces the damage of critical strikes, so this item will be very effective against heavy damage dealers that always attack the tanks first (I don't know why).

Sunfire Aegis Is always one of my recommended list for every melee tanks (for some reason, some make the ranged ones be tanks). It deals damage on every nearby enemy (except towers), thus making it an exceptionally effective item during team fights. A must buy if most of the enemies are melees, but still recommended even though the enemy is ranged, cause you're a melee and must go near them.

A get along with Titanic Hydra. Iceborn Gauntlet deals bonus damage with your basic atk after a spell and slows nearby people. Titanic hydra has damage, so this is not really recommended unless you buy damagous items. But if you are really insistent on not buying Rylai's Crystal Scepter, this will be the replacement.

A good item to be an offtank. Zeke's Harbinger gives you bonus magic damage at 100 stacks, giving you great opportunities to deal large damage during that time. Or maybe if your Ability Power is high enough, It increases the percentage of health done to the opponent. Recommended to link with anyone except the support

Nice amount of armor. Thornmail really gives you an advantage against melee AD people. The best about its passive is that you can start attacking people without the fear of not returning any damage to them. Use it if there are quite a lot of AD melees (in the opposite team... duh....).

Now the magic resist.

Banner of the command will be better than Aegis of the Legion if you want to push faster or you want more AP. It gives you cooldown which would be good for your Tantrum, and gives you enough AP that you want.