Hello guys this is my guide for Skarner, The Crystal Vanguard

Pros

-His very mobile.
-His q slows so freaking much.
-He´s an scorpion.
-He can shut down an enemy carry in team fights very easy (ult)
-He can deafeat almost anyone in a 1v1 situation (counter jungling ^0^)
-He can easily carry a team if he gets fed early on

Cons

-Easily kited by some characters (Ahri, Vayne etc.)
-Need to get close to be effective
-His ganks are mediocre until lvl 6
-His speed buff can be removed easily

As you see he got much more pros then cons and it was really hard to find big cons.

Skarner has a huge variety of runes choices, but i like to go with Attack speed--->Armor--->Magic resist per level--->Armor Penetration

For masteries i go for 21/9/0

I Have tried many combinations of masteries but i find the extra damage from the offensive tree invaluable. And my jungling goes a bit faster with these masteries and i dont find any troubles of sustaining myself.

I start with a Cloth Armor and 5 Health Potions.
This start will give you the best sustain which is the only con about Skarner