Skarner-
Skarner is a champion that lives and dies by his pillars.
Skarner is very unique in the fact that he can actually gain and lose stats based upon what pillars are alive on the map.
There are 6 pillars in total that give skarner not only attack speed but movement speed and increased mana regeneration.
There is one in each river and one in each quadrant of the jungle per red side and blue side.
These pillars are called Crystal Spires.
Skarner can 1v1 most junglers early and sometimes mid-late depending on matchup and items if he is standing on a pillar however he becomes a pure CC bot for ganks or if not fighting next to a spire he has activated.
Skarner also has an extremely quick clear speed early because of these pillars which also grant a few pieces of gold when "captured".
Skarner is mainly played to be able to tank damage and abuse his early ganking prowess with his huge amount of cc.
When you are thinking about picking skarner you have to first check if there are any hard counters.
There are two main counters to Skarner which are Olaf because he can ult and negate Skarner's entire kit or Tahm Kench because if he eats an ally during your ult it cancels your ult.
Skarner can also be hard countered by QSS so you are on a timer a lot of the time because as the game goes later more people will be able to buy qss and even stat-wise you start to fall off because other champions get tankier and do more damage than you.
However, with all this said you are pretty safe to blind pick in solo queue most of the time, and your team will love you because you will be ganking a lot and playing a tank which a lot of laners like as you can play main engage and donate them kills.
He is pretty low on the damage front so hard carrying is not really an option but there is more than one way to carry a game.
If you invade with your Spires and abuse your early ganks you can get your solo lanes an insane XP and gold lead allowing the skarner pick to really shine as one of the few pure cc tanks left in the game.
Build-
Skarner jungle only has one meta build right now which consists of Turbo Chemtank as most cc junglers do right now with the item being overstatted.
This item synergizes with Skarner probably the best out of any champion as the item on an 80-second cooldown allows skarner to use his ult and Turbo Chemtank on cooldown to repeat gank and abuse his early item power spike.
Most games after finishing Turbo Chemtank you will opt into Deadman's Plate even if they have a lot of AP as it allows you to deal a bit more damage in jungle trades and ganks or skirmishers as well as just making you generally faster to be able to get in do damage ult and drag someone back to your team.
It also offers a lot of HP and armor which work really well on Skarner.
The third item is where the most amount of variability is allowed.
You can opt into a Force Of nature as it gives you a little bit of movement speed and 60 MR and 350 health that allows skarner to get a massive amount of bulk for just 3 items while still having his ultimate threat of dragging back opponents with all his movement speed buffs through items and passives.
If the enemy team does not have a ton of AP then you can opt into an anti-heal option such as thorn mail.
Now covering boots something that will enable you to clear faster gank more and skirmish for scuttles and invades is 1st back Ionia boots if you are able to pull off a good gank and secure a kill or invade.
Naturally, you would think playing a tank you would want to build either Steel Plated Caps or Mercury Treads however because the Ability Haste from Ionian boots allows you to spam your E which will secure you can cc them multiple times in a single gank as well as letting your ultimate cdr become lower allowing more ganking.
Your W also offers you some shielding so losing the passive from Merc treads and Steel Plated Caps won't feel as bad.
Pathing-
Pathing for Skarner is quite simple as it allows you to almost fully clear by 3:15 for scuttle and still be there in time to contest it or take it.
However, there are two different paths you want to take depending on whether you are red side or blue side.
For a Blue Side Clear, you want to start at red buff with a leash and make sure you have your Crystal Spire captured.
You then transition into krugs into raptors into wolves into blue buff.
By the time you are finished with Blue Buff scuttle should be spawning or spawned and before you take scuttle make sure you capture the river spire in case the enemy tries to contest you, you can punish him with your increased stats.
You then want to look for a gank either top or mid and if there is none and depending on whether you know where enemy jungle started either invade raptor/krugs or reset for a bot play if that is your only option.
Red Side Clearing is slightly different as you still want to start bot side this time starting Blue Buff into gromp into wolves skipping raptors into red into krugs finishing with either a top gank or scuttle into mid.
This one is much more straightforward as you can change krugs for raptors if the enemy mid is overextended or just do the standard krugz route into a straight top gank.