Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
First thing you have to know about Sion is his first two skills(Cryptic Gaze and Death's Caress) get 100% of his AP, also his shields protection increase with AP. So this makes Sion kinda invulnerable if you don't get too careless.
A fact=Sion can mid! because in first levels his shield will protect you a lot and do massive damage.
Boots of Swiftness?? Yes because after you stun your enemy with CG you have to move fast, hit him a couple times and then blow your shield for the finishing blow. If they survive still thier health will be too low to stay in lane.
Mejai's Soulstealer Sion is a semi-tank champion and your Enrage skill will help you gain health so you don't die very often
Lich Bane An epic item for Sion you will love %100 additional base damage thing after you stun your enemy :)
Zhonya's Ring A life saver and a massive AP item
Void Staff 40% magic penetration and 70 AP just NICE!
Abyssal Scepter Gives AP, gives magic resist and reducing the enemy magic resist RAPE!
Flash I generally use it to quickly get in range for stun and to escape of course
Clarity You will desperatly need mana in early game so could be a life saver.
Don't get too offensive at early game until level 3 try to save your mana to Cryptic Gaze and Death's Caress combo. Remember if your shield breaks from damage overload you will **** bricks. Dont use Cryptic Gaze to harras your enemys
If you are not midding go to mid hide in the bushes flash+stun+1-2 auto attacks+shiled=GG
Stay in your lane as long as possible after you get your boots you will be all ready to rock!
If you complete at least to Zhonya's you are raping them nothing to say..
IMPORTANT!! In mid game do not afraid of turret diving Sion's shield is very powerful
DO NOT let them break your shield unless you are trying to escape
You can ask anything you like and please leave comments GL HF! :)