Welcome to my guide to Mordekaiser. Mordekaiser is an interesting champion that is usually played as a tank, though AP morde's do exist. I'm here to show you a way to be both a viable tank and a great damage dealer.
I want to warn you: my build WILL look weird, but don't be afraid to try it out - it's amazing! And it truly catches people off guard. :)

(Also, this is my first guide, so it won't be fancy. But I will continue to update, and once I learn how, I will also make it look pretty! :) )

Update 1/30:Going to require comments to vote now, since random downvotes aren't fun, and I know my build looks weird.
Update 2/04:Updated the Item Build; added pictures showing my score. Feel free to message me with screenshots of your own scores! My build works! :)

Runes
I use:
Greater Mark of Desolation x9
x9
x9
Greater Quintessence of Desolation x3


Greater Mark of Desolation These help you farm early-mid game, and let you really get in to wack at any potential harassers. Besides, if you're in a fight, once you've popped Children of the Grave and Siphon of Destruction, what are ya gonna do? Go smack 'em!
Some dodge never hurts! Besides, these work well with the Nimblesstalent, thankfully.. Morde is kinda slow.

/shrug. Who Doesn't like CDR?

Other good rune choices include Magic Pen (though I believe they are unnecessary with this build), Health, and magic resistance. Armor is not recommended.

Masteries
9/21/0. simple. Archaic Knowledge is a must, and the defense tree has been reworked so that it's offensive talent, Ardor is now more viable. Also, don't forget: Even Cho'Gath's Feast is reduced by your defense mastery!

Skills

R->E->W->Q.

/shrug. E is your main farming, harassing, killing, damaging, shield generating--- everything ability. Max it by 9. Get a point in Q at 4 so you can spam skills, then leave it alone until your other skills are maxed. The reason I max W before Q is that it is surprisingly strong... and offers survivability to you or an ally. It synergizes quite well with Sunfire Cloak, as well.

Summoner Spells

Must have Ignite. MUST. MUST. I don't care if you absolutely hate it. Just try it on Morde. Please :)
Honestly though, it's vital for Morde. I use Ignite on like 2 champions. Morde and Annie. That's it. But it's damn near necessary for both of them.
The rest... is up to you. I like Ghost. But whatever. Flash, Teleport, even Heal if you want. Whatever floats your boat. Except for Rally, Clarity, etc etc. You know the bad ones. Don't pick 'em.

This is where things can get weird and somewhat tricky.
You'll want to start off with a Doran's Shield and Health Potion. You should be able to stay in your lane until 1100 gold at least, unless you're being harassed to the extreme.
At 1100, Port back to base and buy Sorcerer's Shoes. You aren't so slow now! Besides, the magic pen is amazing early game. (Even if you're comfortable in your lane, I advise you to get these ASAP. You'll want some "late"-early game and "early"-mid game kills to help fund your build. Though with Morde's lane control power, gold shouldn't be an issue, really. Although Mercury's Treads are probably the "standard" tanking boots, you won't be using them for this build, if you follow my guide to the 'T'. And really, ya won't even need 'em.
Now, the tricky part! Who is on the opposing team? Lots of AD? Lots of AP? If they're AD heavy, grab yourself a Chain Vest. Sunfire Aegis is in your future. However, if there's lots of AP, start building Force of Nature. Always start with a Regrowth Pendant or even two when building FoN, however. (As Morde's abilities cost health, these will be invaluable!)
Now, if you honestly aren't sure which item to start building, think even HARDER! (OMFG?!)
They have well balanced AP and AD. so. Who is getting fed? or Who is scary? Panth? Vlad?
You decide. :)

So, this far you have:

and the beginnings of either

Now, a decision presents itself. If you're being pressured, continue building your Sunfire or FoN. However, if you're powerhousing around, doing as you please, build Haunting Guise ASAP. A touch of AP, a splash of health, and even MORE Magic Pen. Epic, underrated, cheap.

This is where the weird part comes in. I'm asking you to buy a Leviathan. Why? It's cheap, and a decent source of health. The goal is to reach 20 stacks with it. If you do so, you're freaking unstoppable. Amazingly cheap, and potentially powerful item. If you're having difficulties, however, don't build this item. It requires snowballing, and therefor, a strong early or mid game. You have to get kills or assists.

If all is going well, you should have:
- or -
Great! So now you can start building Abyssal Mask. This works out very well if you've gone the sunfire route; it has Magic Res on it. Additionally, the AP will help make your b]Children of the Grave and Siphon of Destruction hit hard. Not to mention the 'Magic Pen' on it is an aura; it helps your whole team. x)
Again, go with the flow of the game while building this item. Wand first, or Magic Res cloak?

At this point, if the game hasn't ended, sell your Doran's Shield to make room for Zhonya's Hourglass - or if you're really ballsy and doesn't afraid of anything, the dreaded Rabadon's Deathcap... yes, on a tanky Morde. TERRIFYING!

So. Endgame:
- or -

- or -

If the game goes on any longer than this O_o
feel free to replace your Haunting Guise with something else. Guardian Angel, Lichbane, maybe?

Morde excels at survival. Even if the situation looks dire, you might not have to run. Sit there and fight! Spam your abilities, generate your shield. You'll be surprised how affective this tactic is. You can regen your shield so fast, some enemies won't be able to kill you before they die or before help comes. Even if you were at 1/4 health!

Pros:
-Extremely powerful early game.
-Excellent lane pusher.
-Cool voice, lol.
-Can become unstoppable late-game. 3v5? LOL kkTHX. 5v5? BAH, I ALMOST BROKE A SWEAT.
Cons:
-If you're doing good, people will claim you're a noob and demand you try a champ that requires "skill". Yeah okay, whatever. I've seen MANY bad mordes. People don't complain about them. So STFU Vlad and go use your imba pool in the corner. Good boy.
-High likely-hood of being focused or ganked. Use this to your advantage. If they come to you, it makes it easier. Morde's slow at chasing.

Give it a try, Gimme a comment, and please- constructive criticism only! This is my very first MOBAfire guide, and my first LoL guide. I would like to continue sharing my ideas, but only if people will take my unorthodox playing style, and give it a shot!

Thanks,
Murasaki no Tora.