Intro (reading this will help you understand my guide better)
This guide is split into two parts, one is a tank guide; The other is a DPS guide. I decided to set it up this way because Mordekaiser fits both roles very well. Many people believe Morde is not a Tank, but I beg to differ. The reason I believe he can be played as a tank is because you can harass very well early game and will often send your lane enemies back to base again and again giving you a good level advantage over your opposition; which in turn allows you to build up your resistances and your sheild faster then your enemies can stack attack damage (AD)/ability power (AP) due to their lack of farm. Also Morde levels very quickly due to his outstanding farming capabilities. So even though he does not have CC we rectify this by using appropriate summoner spells and items.
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Pros and Cons
Pros
- Extremely good farmer early-late game.
- Very hard to kill when your sheild is charged.
- Can solo against 2 champs when you have a jungler.
- Is a cool down (CD) based champ.
- Can get a strong pet from 
Children of the Grave
Cons
- Can be squishy early game when you don't have your sheild charged.
- Uses health as a resource.
- Does not have any Crowd Control (CC) abilities.
Masteries (Tank)
Defense Tree
- Extra HP
- More Armor
- More MR
- Dodge
- 4% damage reduction from everything
Utility Tree
- More Experience (EXP)
- More HPRegen
- A little faster gold generation, this point can be placed elsewhere if you think 1 gold every 10 seconds is not worth it. In a 25 minute game it will generate 150 gold, just for reference.
Summary (DPS)
Runes
- Marks = Same as tank
- Seals = allows you to dodge more and get a speed boost when you do
- Glyphs = same as tank
- Quints = more magic penetration? (MPen) what's not to love?
Masteries
- Offense Tree = more DPS, lower cooldowns, MPen, AP, etc, it's got everything you need
- Defense Tree = more dodge, and survivability
Summoner Spells
- Exhaust - same as tank
- Ignite - same as tank but better due to masteries
Items
- you build up lots of AP making your siphon hit really hard and nearly max your sheild in one cast
- You have less defense and can't last in a 1v2 encounter unless you have a good level advantage
Skill Sequence
- you have more damage output with more ranks in 
Mace of Spades
- you have less survive ability due to lack of Children of the Grave ranks
- You can farm better than the tank Morde
Gameplay
- this part is mostly the same as the tank way except you have less survivability and more damage
- you can use Children of the Grave to harass enemies out of the lane/ build your hp back up
Masteries (DPS)
Offense Tree
- Extra MPen
- Better crits
- More crits
- More AP
- 5% more damage output, magical and nonmagical
- lower CDs
- More effective Summoner Spells
- Higher AtkSpeed
Defense Tree
- More MR
- More Armor
- Higher Dodge
- :D
Summoner Spells
Exhaust
- makes it very easy to kill any champ 1v1 in early game
- allows you to escape ganks with more success
- allows you to run down fleeing opponents and make their ghosts your slave with Children of the Grave
Ignite
- Makes it harder for champs to heal themselves/ be healed by other players
- kills low HP champs that are fleeing
- combined with your ultimate (ult) can deal a good amount of damage to enemy champs
Other good spells
- Cleanse helps you survive better against CC heavy teams
- Flash allows you to chase/escape over walls and dodge skill shots that could have killed you
- Ghost allows you to chase like no other, or get back into the action faster
Spells I don't Approve of
- Heal- your hp regen should be good enough when you tank, and you should not be taking too much damage regardless because of your sheild, and your HP Pot if you are DPS
- Revive- my motto is don't take revive unless you plan on dieing
Gameplay
Playstyle
The following passage goes for both Tank and DPS builds, except when you are Tanking you can afford to be a little more aggresive, and with DPS you should play a little more defensively. Imo it is easier to solo against 2 champs when you are playing tank, and is also easier to solo mid when you DPS.
Early Game (1-8)
Mordekaiser can last hit/farm very effectively, which in turn allows you to level pretty quick. Since he can farm so well it is important to coordinate with your lane mate for getting kills in your lane, and it would be nice to allow your lane mate to acctually get the kills since you get most of your gold from farming and you still get gold for assists. most of your kills will happen mid game-late game anyway. Or if you like getting kills yourself then that is also quite easy. On a side note Mordekaiser does really well in a solo lane (mid included), so if at all possible try to get solo top or bottom if you have a jungler or mid if you dont have a good mid carry. On to ability usage, You want to spam 
Siphon of Destruction and Mace of Spades whenever you can to keep your sheild charged. If your sheild is low or non existant then back up until you can get a good hit with Siphon of Destruction without taking too much damage. Also if you are solo top/bot you want to be defensive until you can safely push without fear of being ganked. When you get a few levels higher than the enemy champs in your lane, you can start to be a little more aggresive. Anytime you get your enemies to port back to fountain you can go back to yours to get a few items or you can stay in lane and beat on their tower if there are no mias.
Mid Game (9-14)
When you get to be around level 8 or 9 it is very likely that you and the jungler on your team could easily take out the turret in your lane (along with the other 2 enemy champs), or if you are mid then you could probably take out the middle tower pretty easily solo if there are no mias and your opponent is dead(you have his/her ghost) or back at fountain. Also If you are not soloing your lane then you and your lane mate could have already destroyed the tower in your lane before this point, since Morde is a very potent pusher. As soon as you take out the tower in your lane then go mid (if you were not already), or go to top/bot to help destroy their respctive towers. Rinse and repeat while defending your lane when you notice them pushing. As a side note getting the Red and blue buffs from here on out is not a bad idea, because they both add to your DPS and killing capabilities significantly.
Late Game (15-18)
In team fights you want to put 
Creeping Death on yourself (if you are the tank) or on the tank (if you are DPS). Smite your foes with Siphon of Destruction and Mace of Spades any chance you get. Putting Children of the Grave on enemy carrys is the best thing to do and then follow up with Ignite and Exhaust to try and take them out, and get an awesome pet in the proccess to further wreck your enemy team. Victory should be around the corner by this point so dont let up your awesomeness til its over.
Congrats
on your victory I'd give you a high five but well I'm not there, so this is the best I can do. :D
Thanks
For checking out my Mordekaiser Guide! I hope it serves you well and please please please please leave a comment if you vote this guide down so that I may take your suggestions and make my guide even better!! Thanks in advance. :D
Also leave a comment if you like it/have good success using it, all comments are welcome. ;)
Build Guide
Discussion (8)
Greater Mark of Armor
Regrowth Pendant + Seals
Greater Seal of Armor for a significant survivability boost early game
Greater Glyph of Scaling Cooldown Reduction
Greater Glyph of Magic Resist for more magic resist (MR)
Greater Quintessence of Experience to level even faster
Boots of Speed
Force of Nature
Rylai's Crystal Scepter
Mercury's Treads
Quicksilver Sash
Abyssal Scepter
Spirit Visage
Randuin's Omen
Warmog's Armor
Ninja Tabi
Sunfire Cape
Atma's Impaler
Greater Mark of Scaling Attack Damage are also nice for 
Greater Seal of Scaling Attack Damage for better 
Greater Glyph of Scaling Ability Power for some more AP
Will of the Ancients for a 
Mejai's Soulstealer if you believe you will get a good amount of kills early game. Also you would get 
