I would like to start out by stating that I am not exactly an MLG Pro or anything, and I have only been playing for a little over a month, however I have put a lot of effort into coming up with this tank build and I like what I have done with it. In my opinion, Amumu is hands down the best tank, even over Rammus, because of his two stuns. As such, I have decided to focus on Amumu as my tank Champion.

My runes may look rather noob, but after reading up a lot on Amumu, I came to the conclusion that there is absolutely no correct answer for what runes you should lose. Instead, I looked at my build and decided the biggest weakness was a lack of Magic Resistance, so I went ahead and focused my runes on Magic Resistance.

Since this is a focused tank build, I clearly just focused entirely on the defense tree. I feel at least the defense tree is pretty self-explanatory. Then, I went into the offense tree to improve my exhaust, because well, slowing them down longer is better. I grabbed the Health and Mana regen from the utility tree because it is pretty useful as well, and then dropped the last 2 points into reducing my time being dead. If I am doing my job correctly and drawing their focus while my teammates kill them, then I will have a fairly high chance of death.

Philosophers Stone: Early regeneration, gold generator, eventually builds into the Shurelya's Reverie.

Ninja Tabi: I prefer this over Mercury Treads because as a designated tank, I expect to stand tall in groups more often.

Catalyst the Protector into Banshee's Veil: This is where the real focus of my build begins to take form. I want items that focus on both health and mana, so I can stand in for a good amount of time with Despair active.

Giant's Belt into Sunfire Cape: The area of effect damage on the cape works perfect for this strategy. Be sure to grab the belt first for the health boost.

Catalyst the Protector into Rod of Ages: This continues the build of both health and mana.

Shurelya's Reverie: Health, health regen, mana regen, reduced cooldowns and I can increase the speed of my teammates that I want to clear house around me? Sign me up!

Randuin's Omen: Health, armor, health regen, reduced cooldowns and can slow down enemy movement and attack speed.

This is pretty much par for the course when it comes to Amumu.

Bandage Toss: At level 1, grab the first Bandage toss so you have a way to close the gap and stun. You will not get the last 4 of this until after Tantrum and Despair are done.

Despair: This will be the number 3 priority after Curse of the Sad Mummy and Tantrum. Get this when those two are not available.

Tantrum: This is pretty key. Getting it at 2/3/5/7/9, this will be the first ability you max out.

Curse of the Sad Mummy: Of course you grab this at 6/11/16. It is his ultimate and you get it as soon as you can.

Exhaust is great because it helps to keep the enemy from running away.

Flash is the best summoner spell as you can use it to jump around and position yourself better whether escaping or on the offensive.