Hey everyone! I am IPwnHao, and this is my first guide on MobaFire. I am currently in plat and climbing up steadily. I main Jarvan IV and Zac in ranked. Zac is a very mobile ap jungler that can gank out of nowhere and can disrupt teamfights very well. Upon the release of this champ, I instantly bought it. I first did not like it, but after some nerfs to some other junglers (Xin, Vi, Jarvan, Nunu) I realized this champ has become the "one" in the jungle. This guide is by no means 100% correct, it is just what I think is best for Zac and how to play Zac most successfully.

Honestly, Zac doesn't need attack speed in the jungle. He replies on his abilities to spam the monsters. Zac scales horribly from AP, so the natural marks to take is magic pen. It adds some damage to the monsters and ganking, not to mention it adds 2 extra damage when you autoatack with machete's at level one :)
The yellow and blues are pretty standard on junglers. If their team is early game based AP (Leblanc, Kass, etc) consider getting flat magic resist blues. Other than that, nothing said.
Other than movespeed quints, which are my favourite, you can also get magic pen or ap quints if you prefer. But honestly though, if you can't catch up to your enemy, then you can't do damage at all! Movespeed also helps clearing, ganking and all that good stuff.

I went 9/21/0 because...well...Zac doesn't need buffs, seriously. Buffs are pretty useless on him. So go for the extra ap, cdr, damage on monsters and most importantly, magic pen. For the defense tree, I went for the early armor and health, early damage reduction and on the higher tiers I went for the late game HP and armor+mr. It doesn't seem like a lot, but with that item build you can get like 120 extra health with those materies.

Since the season 3 meta is shifted more towards the "4 squishy 1 tank", it is your job as the jungler to be the tank. Your job is to disrupt the enemy team as much as possible while soaking up damage for your team so they can do the damages. Ancient of the Spirit Golem right now is the best item for a tank jungler. It gives health, armor and a huge clear speed bonus, plus it's really cheap for it's stats. Bulwark is pretty much standard too, your squishy teammates will be needing that extra mr and armor, which is cruicial for them to survive bursts.
Boots are essential for everyone. However, it is hard to consider which tier two boots to get. Zac has four choices. Ninja tabi, merc treads, mobi and sorc shoes. Ninja tabi is the best for soaking damage, especially if the enemy team is high AD. Merc treads is really the worst choice here, because the passive of the boots are UNIQUE and that passive is already covered when you buy Spirit of the Ancient Golem, so it's not exactly neccessary. Mobi boots are for when you're really ahead, so you can roam around and gank like a boss. Sorc shoes is obviously for the extra damage. Since all your other items make you so tanky, you can afford a little bit of magic pen for that extra percentage damage you can do late game.
Spirit visage is cruicial on Zac. Everytime you use a spell, you're literally killing yourself. To regain the health you can pick up the bloblets. Since Zac's CD are fairly low, he can actually gain a lot of health from picking up bloblets. Spirit visage enhances that.
Sunfire cape if pretty obvious...you have a bunch of magic pen sitting around, why not use that to your advantage and burn people constantly with magic damage? It may not seem like a lot, but over time it will accumulate to a few hundred damage, just for standing beside your enemies!

7/22/13 started guide, no idea how to use mobafire.