Hi there, Im the man with an Ideantiy Crisis, though for the moment you can find me under the Summoner Name: Adrrock

I'm a gold 5 Scrub that plays way too many normals, and my hard on is hardest for sion.
That being said, this is a general guide for Sion that Ill be updating as I go, I play him way too much as it stands and have been seeing guides I simply dont agree with, not to say that those would be wrong, but as any proud scrub, I think my build is better. Give 'er a whirl, and I bet you wont be dissapointed

cons

- Sion has almost no pre 6 gank potential
- Early Sion can be invaded with relative ease
- Falling behind means going full tank, which isnt fun
- Takes a bit to get rolling
- Slow

pros

- Post Six Ganks are almost guaranteed Kills (think if Vi was a train)
- Deceptively durable
- High base damages
- Powerful Crowd Control
- Strong Initiate for team-fights
- Revival Passive for those last few hits
- Effective skirmisher
- Best Bruiser (approves by my opinion alone :D)

Starting with Marks: Sion scales silly well with flat AD, and rarely are you looking to really penetrate, with a 1.8 AD scaling on Q and a similarly high scaling on R, base AD gives you better clear and more powerful ganks.

Seals: Armor; the safer clear, general ganking defense runes

Glyphs: A little bit of flat MR to help you tank some mid/support damage, with scaling marks to make sure that defense increases as the enemy mid's damage does

Quints: Sion is slow, the movement speed helps him position in fights, to get them Dirty Q's on the right people, and a little bit faster around the jungle, meaning you can ward faster, clear faster, and gank faster.

9-21, its the way to go. In all seriousness, Sion has alot of AD and the defensive tree allows you to survive being in fights, which you're going to be, without having to as heavily invest in defensive items, meaning that your items can help with clearing the jungle and ganking for much of the early early game, while allowing you to transition late to a powerful tank/bruiser depending on how the game goes. We grab the points in CDR because thats going to determine how often we can use our most powerful ganking tool, Unstoppable Onslaught, while also making our clearing tool, Decimating Smash pop up more often.

Standard Leveling path for Jungle, you can level Decimating smash first if you're running an invade, as you're only going to miss about 12-20 HP, and securing kills/buffs is well worth it in gold. If you happen to be laning against high mobility top lanes max E, W, Q, as you're unlikely to land Q often enough to offset the mana costs.