Hi guyz,
this is my first build guide about LoL.
I hope that it will help some people that have problems with Dr. Mundo to play him better and don't refund him, because actually he is a great champion, that work great even without nerfs :) (referring to Rammus, who is epic aswell).
This is just a build guide, in which I show and explain to you, why I think that everyone is able to play Dr. Mundo. If you should be looking for a guide that shows you how to play Mundo, please look for another guide. I am just explaining on how I build him, and why!
(I have had it up to here with hater comments!!)
Please don't downrate this Guide, just because you would do something differently.
Have fun reading and trying out this guide,
Yours
dsphhz

Dr. Mundo is one of the best tanks in the League of Legends. His abilities allow this weird sortof human to survive almost every combat, gank, teamfight and a lot of teamganks aswell. His Ultimate heals him for about half of his maximum HP within only 10 seconds and boosts his movementspeed, which allows him to even turn the tide if the is about to die (but I don't recommend to try that out).
His Infected Bonesaw deals massive damage, and therefor is one of the most powerfull non-boostable ability in the League.
He can also use his pain effectively, increasing his damage by a flat amount and by a bit per percentage that he is missing.
He is also able to toggle Heart Zapper, a spell that drains his HP and damages all enemies close to him.

These abilities allow him to take down almost every other champion of the League, without even risking to lose many HP...

Starting Items
So for me, the starting items are quite self explanatory: get your shoes and potions as quickly as possible. As an alternative, you can get yourself a cloth armor and two additional potions, but only do so, if you know that you will play against an ADC...


Earlygame Build
You build these items for a bit of earlygame sustain and mainly that you can actually finish your core build as fast as possible.

I know that you won't have that much of money, because Mundo isn't a good earlygame player.

So basically your job is to provide the earlygame sustain for your ADC (that you are playing together on a lane with, of course).

Get the Ninja Tabi if you notice that the eniemies have a very autoattack relient ADC on your lane.
In any other case, you can choose a pair of Mercury's Treads and you won't actually notice a big difference, due to your job of just being there and soaking the damage.

Midgame Build
Ok, this is your/my midgame build. This build is actually the most important part of the midgame (aside your skill of throwing Cleavers), and a very delicate situation: If you build to many "low level" items (i.e. Ruby Crystal) you won't have the sustain and the supporting abilities to actually be a good tank/bruiser. But on the other hand, if you should try to build only "high level" items (i.e. Randuin's Omen) you will end up with two or three items and loads of deaths.
The tricky part is to actually find the balance between buying fully built and starting off items.
Usually in the midgame, my build looks a little something like this, but of course this varies from game to game.


Early Lategame Build
Now, this is actually mostly the most of my build you can reach in one game, because either you're fed too hard and the enemies hit the surrender button, or your team did that because they have fed to much.

In the game, you will start to notice, that from the point on, that you include a Warmog's Armor to your Midgame Build, you will become more and more fed. The interesting part is that you will not die anymore, and instead get one kill after another.
The clue I can give you to solve the mistery about your undying Mundo is: Regeneration.
That's right, by the time you reach level 16, you won't even need to recall anymore, you'll just wait 15 seconds until your Ultimate us up again.



Full Build
This is actually just an addition to the previous part of the item build, so basically I will just explain the two new item:

Sunfire Aegis: added due to the damage per second and small HP bonus it grants you.

Frozen Mallet: I included this item because of the passive slow and the huge amount of HP it grants you. This item makes you more of a supporter that a buiser but never mind...


Core Items
These two items grant you (in addition to the other ones of the Midgamebuild)enormous regeneration.
Take that as your advantage:
Healing 60% of your maximum HP in 10 seconds plus 6% flat regeneration through your Warmog's Armor and your Passive makes 66% of your maximum HP healed in 10 seconds.But didn't we let out something in that calculation?
We did, codeword: Spirit Visage.
This beautifull item increases all healing, health regeneration, life steal and spell vampirism effects by another 20% and decreases the cooldown of your Ultimate by 15%.
Let's just calculate that through:
4408HP x [0.66 + (0.66 x 0.2)] = 3491.136HP

You can regenerate 3491HP in 10 seconds, devided by 10 that equals 349.1HP per second. Tell me what you want, but that is a huge regeneration bonus for level 16.
And in these stats, we didn't even include the "normal" health regeneration, what would make another 40HP per 10 seconds.
With these stats, you're basically unkillable (exeption: good Team Ganks)...

I would perk Dr. Mundos Abilities like that, because he actually has two good Abilities for farming Minions: Heart Zapper and his Infected Bonesaw.
If you do not believe me, try it out next game ;)

I also chose to upgrade the cleavers frist, because it is the best in terms of cost and utility: it deals about 20% of the enemies total health in magic damage, and therefor is his best harassment ability.

His Heart Zapper is the second ability I fully upgrade, because it is a very usefull farming tool, but in the beginning, it is almost just a utility spell, due to its tenacity bonus.

And his Blunt Force Trauma spell is just good in the later mid- or the endgame, due to it's high flat damage bonus. It is very usefull at taking down towers, but due to the fact that the towers actually get stronger the farther you have pushed, you will need this ability earliest in the late midgame, when you will actually have reached about level 15/16.

So, further up on this site, you can see the set of Masteries I use on my primary account. You might ask yourselves: "why put so many perks into the defensive tree, if you could use the more effectively in the offensive tree?" Well, my decision to build Mundo like that, although he needs the kills he can get, is based on the number of enhancements to his given stats (and by the way, he only profits of AP, and that would make him a caster not a tank): Get all the HP-bonus perks you can grab on the defense page first, that is actually quite self-explanitory on Dr. Mundo (but for those who don't know: he uses his HP as costs for his skills).
I the recommend to then go for the armor bonus and everything that reduces the amount of damage you take (again, in earlygame, the high costs of Mundo's spells are actually visible if you take a look at his healthbar while using a skill...). This is just there for the earlygame sustain against any kind of enemies.
The next priority should be the reduction of CC on Mundo, because it firstofall stacks with his Heart Zapper, and secondly just makes his less vulnerabul to Earlygame ganks and Lategame team ganks.

After choosing your perks in the defense tree, i would recommend to take the movementspeed bonus of the utility page and aswell the improved recall perk (1 second is a big difference if the enemies are showing up on your screen and you are in the middle of a recall).

And last but not least (well actually it is) i would recommend taking advantage of the mastery Summoner's Wrath , which grants you a bonus on your summoner spells Exhaust and Ghost (an alternative would be Summoner's Resolve , which would grant you some boni on Heal and Barrier)...

I think that playing Dr. Mundo offers you a great variety of Summoner's Spells, well in fact it allows you to try out every spell, depending on what you are trying to do.
But because this set explains a dual-lane Mundo, I would recommend you to choose between the followning spells in combination: Ghost (for an agressive Mundo or a jungler), Heal (Supporter or just any type of Mundo), Exhaust (Supporter), Teleport (just a good allrounder) and Flash (also just a good alrounder spell).
I personally think that the combination of Heal and Exhaust gives you the sustain and the CC to get as many kills as possible...

Now that you know all of this, it is up to you to choose, which type of Mundo you will play.

In my opinion, there are three types of how to play Mundo in a dual lane:

1. The Supporter. This player is there to provide his lane with sight wards and his teammate (perferringly the ADC) with whatever he needs. You will need to build Mundo a bit differently. For example, you will not buy a Sunfire Aegis, instead you should buy the Ruby Sightstone and lots of wards. You should also try to grant or enable your ADC lots of kills, so he won't be pushed down in the Midgame, where normally the APCs are the strongest ones. Also try to poke and harass enemies with your cleavers (nice amount of damage).

2. The Tank. Basically that is your job: to be a living shield for your teammates. This is more or less the type of Mundo, that I showed you the build to, and he is very effective in surviving even the largest teamfights.
Try to get some kills in the early game, so that you can actually build yourself some early game tankiness. In fact, your best weapon as a tank is your sustain: if you should get into a 1v1, just activate your Heart Zapper and Blunt Force Trauma and start spaming your Cleavers.
This is a good method to get quite a lot of kills throughout the whole game. And while we're at it, you should try and tank the enemies towers if it should be necessary.
Well, now that I wrote all of that down, I noticed, that you are actually more of a bruiser...well, never mind :/

3. The agressive Player. This is a type of Mundo playing, that I personally don't really like: you basically play an AP-Mundo-Tank, that has less sustain than my build, but is built with a huge amount of Spellvamp, so that you actually don't really notice it. The main focus on this type of Mundo, is on his ability Heart Zapper, and therefor he is quite deadly (180 Damage per second minimum).
This Type of Mundo actually needs a build, that is compeltely different, and therefor I will not list it here.

Ok, now because about dozens of people asked me to inklude this, I will now include the section about what my build can offer as pros and cons...

Pros:

You can play him as either a support or straight forward as a tank.

You will have loads of damageoutput as well as a lot of tankiness to survive almost every 1v1.

Cons:

In the lategame you will not be as good as other players in terms of damage...

Aswell in the lategame you won't support anymore without items, because you don't actually have lots of CC...

Aaand, now comes the summary of my Guide.

Overall, the build I have made for Mundo is actually more or less a midgame build.

It will allow you to deal tons of damage and tank almost everything in the midgame.

You will just do your job and tank, throw a cleaver or two and eventually do Baron Nashor (other story) to help your team win. Alternatively, you can (as almost every other guide mentions and I forgot to) you can tank turrets while actually solo-downtaking them in the midgame.

Just try it out,
with best regards,
Dsphhz