I am Mortrius (as the site says), and this is my build on Skarner (also obvious). I am still new to Skarner, and I wouldn't nearly consider myself experienced. This is my first guide. I haven't even hit level 30 yet. I tell you all these negative things beforehand to let you know that I am not trying to sell this guide off as a masterpiece, or even as an obscure work of abstract art. I've been playing with Skarner builds, and this is the best one I have come up with thus far. If you have any suggestions, PLEASE give them, and give them constructively. Do not take anything I say in this guide as law, at least until this build has been altered to excellent standards. Also, this build is used to lane with a partner. I've never soloed with it before. Since you have now been warned, I shall proceed.

Greater Marks of Insight: Magic penetration is good, and since Skarner has great sustained damage potential, I think it's best to make sure that damage is going to happen.

Greater Seal of Replenishment: Skarner has mana issues early on, and sometimes even into late game if you are constantly going at minions and champions alike. These provide a buffer that will allow you to keep spamming Q during a teamfight, and keep dropping your shield when you need it, especially in his crucial earlygame.

Greater Glyph of Fortitude: The reason I picked flat HP runes was because in the early game, Skarner is very squishy. He can fall apart quickly if you aren't careful, and even if you are you can sometimes get obliterated by a mean little duo of damage champs with ignites and exhausts. This gives him just a little extra HP for those early levels.

Greater Quintessence of Shielding: As the game goes on, you want to end up as an offtank. With the items currently in this build, Skarner's magic resistance is lower than his armor. This helps to even things out and make him a better tank against both types of damage.

I'm not going to go through each individual mastery I chose, since some of those are a bit obvious. I will go into detail about a few of them though, especially those that look as though they might be better substituted for something else. As I said in the introduction, I'm really looking for ways to make this better, so if anyone has any better ideas, please let me know. Also, if you'd like an explanation on any mastery that I did not list, please tell me.

Archaic Knowledge + 9 in Offense: Skarner is an AP, and I put points in here for the same reason I use Magic Pen runes; Skarner has to be able to deal the consistent damage he offers, and this allows him to do that.

Quickness: Skarner's Q allows you to slow the enemy from the second hit forward, as long as you keep spamming it, and as long as you can keep up with them. Sometimes you get minion blocked, sometimes another champion gets in your way. This helps you to keep your enemies just in range of your Q so that you can continue to slow them until they die.

Early Game: I begin with the Ruby Crystal, and then Heart of Gold, for two reasons: 1) Skarner is squishy early game, and you need all the life you can get 2) This lets you build faster. The sooner you build, the more you live, the more they die. Simple. The Boots of Speed are bought after these because, now that you have some survivability and building capacity, you need a way to keep up with your enemies while you spam your Q. These let you do that.

Sheen is next on the list. This item is wonderful with Skarner! You can activate any ability and do more damage with his next attack. This is fantastic, especially when your enemy realizes that he or she is not going to take you down and starts to run away. This combines excellently with your Q to let you slow them, then smash them for some extra damage.

Mid Game: As the game progresses, your power should increase exponentially. Mercury's Treads will start you on the path to offtank, allowing you that nice little Tenacity buff and some extra magic resist. Malady comes next, and what a beautiful item this is. Malady increases your attack speed, which triggers his passive more often, which leads you to use Q more often. It also increases your Ability Power, and has that nice little effect that will let you shred your opponents if the fight goes on long enough, dealing magic damage and reducing magic resistance. You are now a beast.

Late Game: At this point, your damage potential is excellent. You will likely become a target for your enemies in team fights, and survivability is now key. There are two things you can do now, depending on the circumstances: You can build Randuin's Omen, using that Heart of Gold we bought earlier, or you can build a Banshee's Veil. This of course just depends on whether you are up against more magic damage or physical damage, so take your pick based on that. Once one of these is built, you can increase your damage potential with a Rylai's Crystal Scepter, making your Q an even more powerful slow. Then, if the game has lasted this long, you finish the build with a Lich Bane and whichever tank item you didn't build before (Randuin's Omen or Banshee's Veil).

The thought process behind the skill sequence is fairly simple. You spam your Q, and so you need it as soon as possible. Your E is only so useful: the heal is too small to be potent enough to let you really survive. It can be used to harass, and while harassment is useful, I would much rather kill someone. So, I level Q first for damage, and switch between that and your W. That shield will let you live through some fights by just enough to get the finishing kill, turret dive, and let you escape or get some extra damage out of you. It's too useful to pass up until the end.

I use Ghost and Exhaust for one reason: They let you keep your enemy closer. There are numerous occasions where you get stunned or slowed. These let you speed up or slow down your enemies accordingly, allowing you to catch up and spam your Q once more!

I suppose I don't have much to add. If you have any suggestions, please let me know; of course, I already said that in the introduction.

8-29-11: Modified to a new potential build that seems to be working pretty well so far.