This is my first decent guide and I decided to make it a Sion guide. Sion is a strong jungler and the best way to play him is to gank a lot and counter jungle a lot. So you must ask for CV from your support everytime it is possible to go ruin the other jungler's jungle.

The reason I pick these runes are,
Marks: A little armor pen for late game in case they start stacking armor and a little attack damage for higher crits. Doesn't make much of a difference but it's something.
Seals: A little attack speed doesn't harm anyone and some armor to be more tanky and for easier jungling.
Glyphs: Magic resist to receive less magic damage (duh).
Quints: The only thing that's better than armor pen is MORE armor pen.

But then again, runes are optional and these are just my preferences.

Just some tanky/AD items. Madred's bloodrazor is good for taking down their high HP chars and more options for example are: Phantom dancer, Infinity edge, Tiamat, Quicksilver sash against strong CC, Youmuu's ghostblade and The Bloodthirster. I like to play Sion this tanky because If you are doing well you WILL get focused, and with these items, you're not going to die and therefore, you are very hard to kill even if you are being focused. Cloth armor and 5 pots are pretty solid for safe jungling and it allows you to finish your first route perfectly. If your team has heavy AP, skip Stark's Fervor and get Phantom dancer instead. If their team is really squishy get Wriggle's lantern and then Infinity Edge instead of Madred's Bloodrazor.

Try to go this route

- Enemy golems
- Your wolves
- Wraiths
- Your golems
- Recall
- Blue Buff
- Wolves
- Wraiths
- Lizard buff

Don't be scared if you finish your mana by spamming your shield on golems but just make sure you have around 50 left when you're done. If your mid is willing to pull blue buff after you finish enemy golems then you do blue buff immediately after that. Also, if you see a really good ganking opportunity i would go W-E-Q-E-E-R at first.

Note: Once lvl 4, start ganking like you are angry, coz then you have your stun. More on skill sequence below.

I pick ghost over flash simply because its better for chasing down enemies. Other options are:
Flash: Good escape ability. Good chasing ability. Really good ability but ghost imo is better for Sion.
Heal: Pretty useless in late game and plus it gives you 50% reduced healing which is a living hell for AD Sion.
Revive: If you are planning on dying.
Exhaust: Also good for Sion if you are against a strong AD carry or just wanna kill someone that's trying to run away.
Teleport: If you are solo top. Then I would build Sion a bit differently though.
Clarity: You got blue buff already.
Cleanse: I tried cleanse for a while and I liked it but it's not something a jungle Sion would use imo.
Other spells: Skip them.

Hope you enjoy this guide as much as I do and if you give Sion a chance you will see that he is really fun to play and if you are fed, your team wins. Just remember to focus their carry by stunning them and 3 shotting them ;)