Hello, this is my first guide. I'm going to be showing you how to play a very good Mordekaiser.

1. Farm A Lot
2. Harrass to prevent enemies from farming
3. Dominate your lane because of Harrassing
4. Be map aware.
5. During Teamfights get right in the middle of it
6. Don't be afraid to die, however don't feed
7. Aid your team

Pros
Tanky
Potential to do a lot of damage
Can get someone's ghost making it a 6v4
Hard to Kill

Cons
Can be shut down early game by powerful champs
Not the best 1v1

I have 9/21/0 because of that your building tank and late game your gonna be on top of all 5 of them, needing a lot of defense. It's nice early game to have a little bit of AP to increase your harrassing, gaining ocntrol of the lane and shutting out your opponents farming, which will really hurt them late game. Also all of the small stacking of armor and MR in all of these really makes a difference early-mid game when your not stacking resists.

Reds - Insight for the magic pene, allowing you to really get those champs with somewhat low MR early game.

Yellows - Armor makes you more tanky, obviously. Makes it much harder to kill you, however it doesn't make you invincible but a nice bit better.

Blues - MR also for being more tanky, balances out the armor. See above.

Quintessences - Your preference, both the health (26) or the regen for more sustainability, but I know that everybody doesn't have all of the quints, atm I think i'm just using AD because I have nothing else but the health and the regen prob your better bets if you have.

You need all of your abilities by level 3 for sustainability, as there are some powerful early game champs, like Gangplank, other AD carries. You need to just survive with some decent health till you get to level 4 but still try to harrass. At that level you'll just be hammering out their health. If you see them slightly glow it means they're trying to get an attack or ability on you, avoid if possible, or Mace some nearby minions for a basic shield then Siphon the enemy champ. Past that your maxing out Siphon while having the Metal shield things, at a decent skill level.

Your gonna start out with a Regrowth Pendant and a potioni for keeping sustainability. Your going to start making a Mercury Treads, usually, however if their team is almost completely full of AD like 3+ AD carries, then go Ninja Tabi, and that means some changes in the build. Then your going to get a Giant's Belt and then a hextech revolver. Should be around 6-10 now and soon your going to finish the Warmong's. This is your item that helps so much. Now your going to build a few counters, usually a Thornmail for the AD carry(ies) they have. See below.
After you've done that for your last item you'll either get a Rabbadon's for the AP or some more armor/MR. Late game build Hextech Revolver into a Will of Ancients.

Up top i have what the optimal tank would have so if the enemy team has every type ( tank, ranged carry, and melee carry, offtank, and support) you MIGHT need all of the things up top.

Generally mostly you will need on Warmong's for defense until late game. Some defense items are listed below. I usually only end up getting Thornmail if they have 2+ AD otherwise i'll just get some more AP

Like I said if they're full AD your gonna want a Ninja Tabi, Thornmail, Randuin's in your build. The idea is that they'll have someone hopefully without Lifesteal (which counters Thornmail) and then you'll ult them while you laugh and watch them kill themselves attacking you. I've won many games like this.

AD Counters - Thornmail, Ninja Tabi, Frozen Heart (though someone else should probably get this as you do not gain from the man in this) Randuin's Omen.

AP Counters - Abyssal Scepter, Force of Nature, Banshee's Veil.

Many of these items are situational, and I feel like you kinda know what they do and if you'll need them or not.

With Mordekaiser you should never be thinking about how you can ks, or not die while still getting a kill. Your job is to annoy the enemy sooooo much that they attack you, which is what you want. So your team can kill them. They will overestimate your abilities and damage and so sometimes they might focus you. And if they do not, just run around spamming your spells. In teamfights your place is right in the center, spamming all of yor abilities on everyone since they're all AoE except your ult. Your ult goes on their AD carry, if they have 2 or more the weaker, ranged, and one without lifesteal. Ignite usually goes on the same person as your ult because of the more damage since you are not doing the main damage. The idea is to get them to kill themselves, while your team takes them out. YOU DO NOT CARE IF YOU DIE, only that you WIN THE TEAMFIGHT. If you survive, awesome if you don't and you won teamfight, great, your team will push and you will win.

YOU MUST FARM A LOT. Every time you run from one lane to another, take out the Wolves, Golems, and Wraiths, and if your team isn't actively getting red/blue it's yours to take. Mordekaiser is an amazing farmer. Get in the middle of all 6 or 7 minions put W on and then Q and then whoever's not dead E. If you farm very well, you will really shine mid game when the teamfithts start.

1. Lots of Health which you will need because generally you will not get very much resistance.

Warmong's > Frozen Mallet and Rylai's because yes slows are nice, but if your depending on the slow your probably not going to melee attacking them. You do not need slows, you are a damage soaker. That is why you have Spell Vamp and why if your going against AD especially ranged and ones without Lifesteal you have Thornmail because I believe you get the spellvamp off of the damage. If your team needs slow and a tank you should not have picked Mordekaiser.

Recently made as an answer to the comments.

I know we all love Rylai's the slow, the health, a bit of AP. Well that's all nice but generally you will not need this. However there are some cases where I do too, get this, that is only if your team is seriously lacking on the slows, this with your ult will be a 10 second slow. However people this is much better than it really is, if you are needing health for for Warmong's, about the same price a bit less thatn 3 times the health. If you are looking for damage ( which between your ult and ignite, you do a decent ammount of dmg to say a Vayne, or MF or something ) then get a Rabbadon's.

Hope you enjoyed my guide, sorry it's kinda boring not sure how to do all the pictures and stuff, I might add a video in if you guys like this. Please post comments below and i'll get back to you. Sorry about the mistakes I have made, and how this isn't very pretty, it's my first time. If you have any questions just ask.