To start my Mordekaiser Guide lemme say that some of the items I suggest you will also see in udyers guide to Mordekaiser. Now then lets go over the basics of Morde shall we?
Summoner spells: My personal favorites are ignite(an absolute must) and flash(this can be traded for something else if you really want like teleport or exhaust your choice)
Passive Iron Man:20% of damage Mordekaiser deals with abilities is converted into a temporary shield, which absorbs incoming damage. The shield Decays by 2% a second
Mace of Spades: On next hit, Mordekaiser swings his mace with such force that it echoes out, striking up to 3 additional nearby targets, dealing his attack damage plus 20/40/60/80/100 bonus damage.
If the target is alone, the bonus damage is doubled.
Creeping Death:Unleashes a protective cloud of metal shards to surround an ally, increasing their armor and magic resistance by 10/15/20/25/30 and dealing 20/35/50/65/80 (+0.15) damage per second to enemies in the cloud for 6 seconds.
Siphon of Destruction:Mordekaiser damages enemies in a cone in front of him, dealing 65/110/155/200/245 (+0.4) magic damage.
For each unit hit, Mordekaiser's shield absorbs an additional 8/12/16/20/24 health
Children of the Grave: Curses an enemy champion for 8 seconds, stealing 3/3.5/4% life per second, plus an additional 0.1% per 50 AP.
If the target dies while under the effect of the curse, their soul is enslaved and will follow Mordekaiser for 30 seconds. During this time, Mordekaiser gains 25% of their ability power, and attack damage. The spirit gains 65/75/85% + (+%) of Mordekaiser's adjusted damage, ability power, and 50% + (+%) of Mordekaiser's health.
For this Mordekaiser build the spell list will go as follows
5.) W(Here you have a choice if the lane you are fighting is very squishy I generally forgo W until around level 8, but if they are putting out pressure this is a good time to take W)
8.) E (Or W here as mentioned above)
1.) Doran's Shield and 1 Health pot.
2.) Boots of mobility or mercury(only if heavy stun/snare)
3.)Phage -> Frozen Mallet
4.) Giants belt -> warmogs armor
5.) B.F. Sword -> Blood thirster
6.) Sell Doran's Shield -> Atma's impaler
(most games dont go much longer then this but if they do)
7.) B.F. Sword -> Infinite Edge
Levels 1-6: Getting started
Middlekaiser:If you get to go mid (yay!) then start by scoping out who you will be playing against. Be aggressive as morde as the more you use your abilities the harder you are to kill using E to make sure you hit as many minions as possible is best to keep your shield at full (but always aim for champions over minions). When using Q think about the ways it will bounce often times if you line it up correctly you can tag a champion with it and, it is also an awesome farming tool. During your 1-6 time you should be able to net 1-2 kills on your opponent and have picked up your boots during this time.
Lanekaiser: playing Morde in a lane is also very viable. The best lane partners for morde is anyone with: a stun, snare, or slow as morde does not have one early game. To start head into your bushes and use Siphon to scope out their bush if no one is in side head on in and hold it. If someone was inside then they will do one of two things either push twards you looking for a fight ( a bad idea) or they will retreat until minions spawn. as mentioned in Middlekaiser being aggressive is always a good idea if you can manage it. using Q and E to farm minions while hurrassing your opponents. As a Lanekaiser you should be able to net 1-3 kills and get your boots before this is over.
Levels 6-12: Ganking it up (Note I will go over using Children of the Grave later)
Middlekaiser: When this time rolls around you should have killed your opponent 3-4 times and be pretty fed hopefully having your rylais or at least some of the parts for it, this is also the best time to start making yourself known around the map start setting up ganks/helping other lanes if middle is safe (note that while it may take morde a long time to push a turret down he can eventually).
Lanekaiser: in this level bracket its very possible for you and your partner to push down the enemies turret if you have pushed down their turret start making yourself known on the map helping gank middle or top/bottem.
Levels 12-18: Raging out!
Mordekaiser: at this point in the game you should be mostly in team fights and scoring lots of kills. Using Creeping Death on yourself or on a team mate thats getting focused can actually turn fights in your favor because it makes just standing near that person deal DPS to enemies around them and gives them some survivability.
Using Children of the Grave: Mordes ult is always most effective when coupled with ignite you dont have to use it with ignite but if you can do. As this will make the damage pretty much unlivable. Also never forget that this ult does give you life steal so using it when your opponent is about 3/4s HP is great because it will give you some extra life to keep up heavy DPS on them. Of course you should only throw it early if you are going to be DPSing on that target at the same time other wise save it until your target has around 1/4 HP left and you should be able to have your very own little ghost!
---Make sure you pay attention to enemy champions who may have cleanse as they can cleanse off your ult and ignite so be careful about placing it on a champion with cleanse--
Choosing your victim: Who you use morde's ult on is also important because you gain a percentage of their stats and some ghosts are better for pushing turrets and some ghosts are better for DPSing enemy champions and some still are better if you want a little bit more personal DPS.
For Turret pushing:Take out a tanking champion I usually try and pick on Mundo pantheon(because his Aegis can proc) Malphite because of his 10% shield or Twitch if you want some ranged back up
For DPSing Enemy Champions: Choose Carries mostly twitch master yi pantheon tryndamere Teemo is my personal favorite as his passive carries over and you can poison kill enemies quickly. anyone who attacks fast and will give you bonus Attack Damage at the same time
Runes: I use a tanking rune page for my DPS mordekaiser which is
Yellow: armor HP
Blue: CD reduction Magic resist
Archmage's savy: 3/3 Deadliness 3/3
Sorcery: 4/4 Alacrity: 4/4
Burning embers: 1/1 Archaic knowledge: 1/1
Brute Force: 3/3
Resistance: 3/3 Hardiness: 3/3
Well that about sums up my guide comments/criticism always welcome