Some of it wasn't originally in the guide but I have put some in it in my new update. I'm also adding much more depth on the items when I have more time. Like when and when not to use specific items etc.

Alright. Thank you for explaining some of the thoughts behind the guide. Try to incorporate those clearly into the guide (if I missed them, apologies). I'll look over this again in the morning.

I do understand your points but I have played all of these items before with great success. I only say that you take tome against those you hard counter, like akali. Which I've dominated in lane with. His damage early game is not that necessary. His MS is because he really, really need MS. His early damage is fine for what he does best. Farming. Which is all you should do early game. With the occasional harass. I take Rylai mostly for the passive and health. But if I feed I take stuff like Void (I should add to list) It's my first guide and I will add more. I'll also get better at coding. Also the gunblade has a very effective slow and the Q does help late game. I rarely use the gunblade though. It's too expensive for what it's worth but I put there because it's useful. Q only also help morde in trading against Melee AP. And his E is just fine for harass on its own because it's more universal. And I said he's difficult to counter but then I listed his main champion weaknesses. Also the reason I take Spirit is because it's much cheaper than any other 20%Spellvamp item, by far. With a 10% CD reduc that helps and a 30+ monster damage for Wraiths and Wolves take.

Runes look fine.
I dislike AMp Tome on Morde due to your lack of sustain in the early game. If you were going Spell Vamp Quints, maybe.
Rylai's/Liandry isn't as good on Morde as one might think, the straight damage you get from Void Staff for instance is much stronger.
Gunblade shouldn't be a recommended item for Morde.
Core looks alright.
Masteries are largely flawed. I dislike 9/0/21 on Morde because he doesn't need the Movespeed as much as he needs the damage and early survivability. You took Strength of Spirit despite not having Mana. You took Artificer while only having 1 activated item in your core, and only one more in your situational.
Skill Sequence you decided to forgo Mace of Spades entirely, which is a poor decision. It deals a considerable amount of damage in a straight fight, and helps Morde in trading.
In your Pros and Cons you say Morde is difficult to counter, which is simply untrue. People who can abuse his poor early laning and harrass him when his shield is down are decently common. However, you do accurately list his weaknesses, so that makes up for it.
Guide is short.
Guide has very minimal BB Coding.

Not going to vote, but if I did it would be a -1.

inb4 drew downvoted

Yeah. I've put the C2V up now. I wasn't quite sure what it was so I didn't want to tamper with anything. But now I know so thanks for that.

C2V, btw, is comment to vote. Looks like the trolls really rushed your guide. I'd upvote, but I can't tell the validity, as I don't own/play morde.

Yeah. I do know that I really should set it out better. But I'm only just really getting started on coding, and it's quite difficult to get used to at first. So i'll just use what I can for now. I'm sure this will pick up in time when my skill gets better.

Turn the feature called C2V!

That avoids you the troll votes more than you think.

But anyways, I am not a Morde player, so I can't really judge you on contents, but you should try a bit harder on your readability. Moar BBCode!

I didn't vote at all btw.