***First my english is not really good, watch on ur own risk.***

Sion is a great pick almost in every team. u can build him in a lot of ways that will make u a pain in the other team ***. +

This Guide got 3 builds:

this is not always what i use but 3 of them cover almost all the items that il usually build this means that sometimes, i build Not SHEN first but Roa as first item. but i still build Deathfire Grasp as second and Rabadon's Deathcape as thirt. that will depends on our enemies.

FIRST: cheap way to cap mana problem and still having a Great amount of CDR and DMG at mid game at earlyer ur explosive and almost untouchable in ur lane also is a CHEAP way to get Rabadons Earlyer that gives u a great Burst in the ending of Mid game. (If they dont have A Lot of ADS u can exchange ur Glacial Shroud for 1 Friendish Codex wich u can let it there or finish it to a Deathfires) still cheaper than ROA / DEATHFIRE.
Use this build if their team have enough ads.

SECOND: Expensive way to give ur self a Strong late game but is not that good at early do this only if ur doing it great at early.
Use this if ur doing it great at early (still i dont recommend this)

THIRT: is awesome at early and late game still it doesnt have Lichbane wich is really usefull at late game ur a ganking machine with this build. but ur not that good at Mid.
Use this if... i dont know it is a great build works almost with everything

I be seen a lot of guides of sion in mobafire but i think they have an usual mistake or common mistake. they tell you "Build Sion this Way u will pwn others ONLY if u use him like this not caring who ur enemies are." and thats the mistake sion is a really flexible character he can solo top support a duo lane or even go to mid doing a great job. he can build in so many ways, thats what im going to explain next.

*Sion have mana pool issues this means u need items that gives mana to give u a good start.

*Sion Skills scale great with Ability Power still ur Q and W at lvl 5 got a base dmg of about 500 this means u will be hurting them without mana for 800 with this combo even if u dont have ap. (its not enough of course because u have to 1 shot them but this means that with Rabadons and another item that gives u AP u will be doing about 400 + per skill. a combo of stun / blow up / 1 hit of lichbane / and deathfires will be around 2.5k in 1 second.

*Sion Job in team Fights is to kill squishys or protect yours. but if theyr squishy is close enough to ur team u should kill him fast or he will dmg ur team really fast.

*Sion Lichbane Should be used Carefully is a great item but u should not be risking ur own life to hit the target once with it. if u can kill him by doing this do it if not just stun and blow up in distance. and retreat.

*Sion Lichbane is great at 1 vs 1 if u go to some1 and gank 1 squishy with LB and Deathfires this squishy will DIE!

*Sion got a Great burst but doesnt have a lot of sustain u should not be autoattacking ppl u need to use ur shield wait 4 secs go stun some1 (use deathfires if u have or ignite depends on health of ur target). blow up and watch them die. if they dont die just LEAVE. and try again later.

*Sion Lategame is really strong u can kill squishys in 2 hits and still have like 4k hp and high defense. ur shield absorbs at this time like 1k dmg this means ur really strong. u will be targeted first but if they do this ur team will punish them if they dont target u, kill theyr squishys if they are close to the team fight or just stun 1 carry and blow up in the middle of everyone.

PROS

*great diver
*great pusher
*Great ganker
*Great sustain
*Spameable stun
*Nice Aoe dmg
*can kill squishys easily (2 hits) + ignite = dead guy
*he is really tankyer
*good farmer
*can solo dragon at lvl 6
*can destroy turrets due to his ult + E that gives him enough ad
*A LOT of health at Late game cause of his E with 100 - 150 minions u will have like 3.5k health and 100 minions is not a good farm at late... with 200+ like 4.5k +

CONS

*u dont have the dmg of 1 Annie, malz, vayne etc. (still if u are the opener and stun them first u can one shot them. its ur job).
*if ur shield is broken half of ur dmg is gone.
*Bad mana pool until ur first set is complete.

i took Flash and Ignite

this is because Flash is a great way to gank or to escape u can flash some1 stun him blow up and kill him in 1 sec by doing this or starting a teamfight killing theyr squishy first.
use it as a opener like ashes ultimate.

Ignite Great at early great at late. u will be targeting squishys ur job is to kill them, almost every squishy got life steal with this + 1 stun explosion they will drop dead. i just dont think another spell can compare to thoses

First at all u will be buiying 1 dorans ring and going to a lane.
Always remember to Harass with Q or W still u have to be really carefull ur mana is not that good at lvl 1 u have like 200 mana that means 2 stuns and ur oom!.
Based on that we need to give Sion a good boost in his mana. thats why i Buy or SHEN, ROA, Deathfire. at early game
With only 1 of this mana boosters u can go oom so with 2 is ur cap or ur relax game time...

Example 1: i bought Shen but i still got mana problems my lane cant die or escaped and i didnt killed him so i cant gank to mid or bot etc. this means that i have to call mia go b buy another item to boost my mana and thats because i cant build deathcape yet damn!.

Example 2: i bought Shen my enemy died in 3 hits i got enough mana so im going to gank somewhere else or i keep my self in the lane farming. so where im going b i can choose between Solving my manas problems buiying a Deathfire or busting my dmg and going to gank building a Deathcape.

Ganking at early is important is one of ur jobs always watch when u can gank in this time
Ur flash + stun together is a great ganking machine.

MID
at Mid game u should be Mana Capped with 1 Roa or 2 Mana items and have ur Deathcape u will be or pushing lanes as crazy (Remember to ward ur lane so they cant actually gank u). or joining big teamfights in 1 lane. ur job will be stay behind and try to creat oportunities for ur team if u can stun some1 that is a bit far from his team in a team fight this guy is dead.

LATE

at this time u should be having all ur items or most of them ur job in here is to try to kill theyr squishys first in about 2 hits or protect yours.

Try to make them hit u at team fights if theyr squishys are in the back of ur enemies. be in front of ur comrades and stun 1 guy eventually will make them very angry. if they start hiting u just stun some1 pop ur shield and try to escape in the middle of ur team mates. this is because ur hiting about 800 per stun but it does have a 5 secs cds this means that until ur cd is not over u should be doing something this is your JOB. after this they will follow u at the middle of ur comrades or just will back eventually u will be hurting some1 enough to make him B or they will follow u and make theyr squishys appear. after the fight start again do the same thing try to focus theyr squishys. and kill them in 2 hits.

SHEN first: Remember u can pop ur shield and wait until u can blow up on ur enemy ***, go stun him hit him once w8 a little bit explode and hit him again and them leave.
This is because ur E gives u a decent amount of AD that will combine really well with ur SHEN

Shen is Cheap that means that u can build 1 Shen and Glacial and that will give u a bunch of good stats that will be synerg really well at early (mana problems almost solved a decent amount of CDR and armor) this is a way i use against ads enemies that works plenty well. and by the amount of a ROA that means that u can build Rabadons Earlyer

Or Buy a Shen and them Deathfires Grasp that have a lot of synergy at mid and cheaper than Roas and them Deathfires this will make ur mid shines as a sun.

ROA first: Remember Roas is expensive as first item but it should be builded as first
This will give u a decent amount of Mana and that pasive that restores health and mana per lvl is great to stay in a lane still this item is really expensive.

Deathfires Grasp: this item shines at mid game as a ganker sion is really usefull he can flash to mid stun blow up and ignite if he have this item he can stun, use the item, blow up, ignite even if mid is a tankyer at Mid game he will not be alive for long if u do this.
It doesnt have a lot of power at late game... it can be usefull but ur Sion u should not be targeting High HP heroes as first targets.
(I dont buy this if they have a lot of squishys).

Abyssal scepter : great at late game MR to survive and make ur self tankyer ability power = damage and magic penetration. ur explosion is aoe this mean that with this item u can stun blow up in the mid of a team fight and dmg everybody by a lot of AOE dmg. Great synergy with ur explosion.

I will Post screenshots in a while just w8 for it... please rate and comments

in comments can u help me about the spelling of some words? maybe a no sence phrase?. i will be really happy if u help me about it. (yes i know there are plenty of them)