^^^^^^^^^^^^^
I'm going to explain certain things jhoijhoi said more in depth.
First-Your summoner spells aren't bad, but it's a very well known thing that mordekaiser and ignite go well together. Ghost is a gimme, because he has no escapes or chasing mechanisms. These two allow you to ghost, siphon, ignite and ultimate, for easy kills ALL the time.
Second-Warmogs armor. It looks GREAT on paper, but is terrible in reality for mordekaiser. Here's how mordekaiser works. His Iron shield ability gives you extra "HP" to shield attacks with. To gain shield, you hit things with abilites/stolen souls/use creeping death. Increasing HP on mordekaiser in HUGE chunks is a bad idea, because the shield doesn't become stronger that way. Armor and magic resist are the way to make him more indestructible. Certain HP items are still good however. Rylai's, Frozen Mallet(situational), Banshee's(situational), Doran's shield, Randuins(situational), and Sunfire are all good or awesome items. To explain each one-
Rylai's is an amazing item for mordekaiser. The ability power will help you absorb more shield, the HP will make it so when some of your abilities are down you can last until the next one comes up. The best part however, is the slow. Mordekaiser has no CC, at all. Ghost is good for this reason, sometimes you just need that one siphon to kill them. However, a slow on ALL your abilities is amazing. Frozen mallet is sometimes paired with this, so you get both slows and a lot of CC if your team needs some.
Banshee-This item is a great anti-mage and CC item. While the mp is wasted, it is still worth it for the shield, MR, and HP.
Dorans-This is strictly a starting item. Look at it only if you think your opponent in the lane will be physical, or the team has more physical than magical. Armor and hp is a good drop for some regen, but will be wasted if they are magic.
Randuins-jhoijhoi is correct-Mordekaiser will never be a true tank that can protect his teammates from attacks. Randuins is a very rare item for him in my opinion, Only for when their team has a lot of autoattackers (caitlyn master Yi ashe etc) on their team.
Sunfire-I saw you were questioning the sunfire on Unforgiven's guide. What you need to know is this: Sunfire is absolutely required on any mordekaiser that isn't straight ability power. This item makes his shield stronger (45armor), makes him tougher when his shield is down,(450hp) and gives him bonus farming/aggro in fights with the 35 damage aura. Stack the damage with your creeping death; you do over 115 damage to everyone each second nearby. This thing kills, baby.
If you saw, each item gave something outside of HP to contribute.

Cooldown is great on mordekaiser, but sorcerers shoes are very important for his spells.

You don't seem to grasp the awesomeness of spellvamp. Let me explain.
Will of the ancients gives 25%-If siphon his 4 minions, 250 each, you will gain 250hp from that attack. It costs 72, so net gain 178. Why is this good? Because when you're in battle, FoN won't give you 1000hp per 5. Spellvamp will.
You NEED to have a written out guide, explaining your choices and such.
Sorry for the ramble, I just wanted to help you as much as possible ^_^ cheers! Jackattack052

Okay, here's my review:

1) You only have 3 Glyphs. The maximum you should have is 9.

2) You only have 3 Marks. The maximum you should have is 9.

3) You only have 6 Seals. The maximum you should have is 9.

4) Mordekaiser has no natural escape mechanism, so I'd suggest adding Flash as a possible Summoner Spell.

5) Tank Mordekaiser isn't great. He's not meant to be built tank. As such, you shouldn't have Warmog's Armor or Randuin's Omen. You're not meant to be the tank, you're meant to be the tanky AP caster. As such, if you wanted an item that gave a whole lot of health, that could replace Warmog's Armor, I'd suggest Rod of Ages or even Banshee's Veil.

6) Force of Nature and Rylai's Crystal Scepter are great items on Morde. Another great item on him is Hextech Gunblade. Not only for the spell vamp, but for the unique active.

7) One of the reasons why Morde is so unkillable is because of his shield. To raise his shield, he has to hit something with any one of his spells. To activate his spells, he has to have reduced cooldowns. This is why some Morde players would definitely choose 9/0/21 Masteries.

8) Your Defense tree masteries are allocated poorly. Why would you get dodge percentage over health regeneration?

9) The actual guide itself isn't written very well, and doesn't really grasp the reader's interest. You need to create sections, learn a bit about BBCode, and run your guide through a grammar/spell check.

Well, hope that helped :)

- jhoijhoi