So...some of you might wonder why I use this build on Cho and what I focus on. To cut it short: As Cho'Gath you have to run into a teamfight, absorb most of the damage and disrupt the enemy AP carry actively, while passively disrupting the enemy AD carry. Your frozen heart will do it's job and is overall a very usefull item, especially as it gives you the CD-reduction most of you are looking for. However the key point is Wit's end. Your enemy will know that you are the tank and shouldn't be focused, however they soon will learn that more than 200 (130 base damage + 42 from Wit's end + (80+ your AP) + Atma's ) damage cannot be ignored, meaning that they WILL have to focus you at some point - giving your carry time to kill them. That's about all concerning Cho's mindset.. You run in, go straight for the AP carry, silence him, do a few basic attacks, eat him and ignite him. As simple as that.

Damage 54.1 (+4.2 / per level)
Health 440 (+80 / per level)
Mana 205 (+40 / per level)
Move Speed 315
Armor 19 (+3.5 / per level)
Spell Block 30 (+0 / per level)
Health Regen 1.5 (+0.17 / per level)
Mana Regen 1.29 (+0.09 / per level)

Q - Rupture - Ruptures the ground at target location, popping enemy units into the air, dealing damage and slowing them.
Ruptures the ground at target location. After a short delay, enemies are launched into the air for 1 second, dealt 80/135/190/245/305 (+1) magic damage, and have their movement speed slowed by 60% for 3 seconds.
Cost
90/90/90/90/90 Mana
Range
950


W - Feral Scream - Cho'Gath unleashes a terrible scream at enemies in a cone, dealing magic damage and Silencing enemies for a few seconds.
Cho'Gath screams in a cone in front of him, silencing enemies for 2/2.25/2.5/2.75/3 second(s) and causing 75/125/175/225/275 (+0.7) magic damage.
Cost
70/80/90/100/110 Mana
Range
300


E - Vorpal Spikes - Cho'Gath's attacks passively release deadly spikes, dealing damage to all enemy units in front of him.
Toggle: Cho'Gath's physical attacks launch spikes that deal 20/35/50/65/80 (+0.3) magic damage to a line in front of him.
Cost
No Cost
Range
40


R - Feast - Devours an enemy unit, dealing a high amount of damage that ignores magic resist. If the target is killed, Cho'Gath grows, gaining maximum health (maximum 6 stacks). Cho'Gath loses up to 3 stacks upon death.
Deals 300/475/650 (+0.7) true damage to target champion, or 1000 true damage to target minion (ignores resists).
If the target is killed by Feast, Cho'Gath grows, gaining 90/120/150 maximum health (maximum 6 stacks). Cho'Gath loses up to 3 stacks upon death.
Cost
100/100/100 Mana
Range
100

Carnivore - Whenever Cho'Gath kills a unit, he recovers 40 - 82 (based on level) health and 8-16 mana.

The skill sequence I described and mostly focus on in the build is only applicable if you are playing a lane Cho'Gath in bot or top lane. If you decide to or have to go mid, i'd recommend to prioritize Feral Scream over Rupture over Vorpal Spikes, just simply because Feral Scream is a more "secure" and "persistent" way to damage a champion.

-Cho is an amazing farmer, with 2 AoE spells and one on-hit AoE. You can just clean out whole minion waves in a second.

-Cho's ultimate does true damage (and makes an amazing sound which all of us love), both to neutral monsters and to champions. It can be perfectly used as a "super smite" to steal e.g. Baron Nashor or Dragon, but can also hit enemies by surprise, because they will underestimate your damage output and will feel secure with 600hp.

-Cho has incredible staying-in-lane power due to his passive and his ability to clean out minion waves in a matter of seconds. When farming, however, try not to waster your mana by using both Q and W, but use Q and let your E + auto attacks do the job for you.

You will have noticed that I am running full AP / magic pen runes and 9/0/21 masteries on Cho. In addition, starting with a Doran's ring and prioritizing Vorpal Spikes over any other skill will give you a super easy Early Game and will make you an extremely potent farmer. I cannot stress the importance of lasthitting! That's the only thing you should focus on until you are level 9-10.

...you finally have learned your ultimate. What I would recommend you is to try to always have as many stacks of rupture up on you as possible (since you gain max.health when you eat someone), however you should think about the likelihood of a teamfight breaking out within the next 40 seconds. You should ALWAYS make sure to have your ultimate ready when you enter a teamfight, just cause it's such a huge nuke and helps you a lot. After playing a bit with Cho'Gath you will get the feeling of when to use it. What I mostly find doing is feasting on a minion straight at level 6 and trying to get 3 stacks up until I recall, just because it gives you such a great max.health advantage over your enemies. However, if you see an opportunity to flash-ultimate-ignite-kill someone... needless to say that you should not let it slip away !

Boots of swiftness - for better chasing and kiting.

Rod of Ages - AP, HP, Mana. Not much more to say. Great item on anyone dealing magic damage.

Wit's end - to trigger your E more often, to deal more damage, to get that extra bit survivability against mages.

Frozen heart - CD reduction. Mana. Attackspeed debuff aura.

Abyssal scepter - MR debuff aura. MR. AP. Again, great item on anyone dealing magic damage.

Atma's impaler - Considering you will have more than 3.5k HP (w/o elixirs), the extra damage is just amazing. Moreover, Atma's provides you with some more armor.