Well, im not gonna say much in my intro, not to be boring and write the lore and so, only thing i have to say is that its the build I alvays use on him and please, dont rate down just because it doesnt look tidy( and it wont, I wont gonna spend more time on him...:P)

I'll just go straight ahead to the business...

well, as any caster marks will be useful to deal that little more of damage, sometimes withour it you couldnt score a kill sometimes. Seals for mana regen so that the spamming spells will be easier and glyphs for a more frequent spell spam...

quit=nts for movement speed go well on him, since he doesn't really have a good escape mechanism, so now he does: this and ghost should do, but the best way is to know WHEN to pull back, playing kog is all about being aware...

kinda typical caster masteries, i tried any combination but with this one i NEVER (at least till now) lost a match...

Offense:
A little more AP can actually wage between life and death
Crit? didnt have anything else to spend on, but actually i think it applies to the BAB...
Precious cooldown, just to spam a little more on the beggining, making you a great harass tool...
and nothing more like a 15% of penetration, coudln't live without it...

Utility:
Let me say in short way, the masteries are aimed at mana regen, max mana(archangel staff boost), movement speed and cooldowns...

It never happened that my item order never gave me a fail, so here it goes...

Early game: grab meki pendant and 2 pots for HP, and try to lane with a tank to cover that squishy butt of yours. If you dont die and farm good(last hitting all the way!) you should be able to have a tear of a goddess, basic shoes and amplifying tome by level 6, rest depends on you: if they have a lot of tanks go for nashor, if they die easily go for soulstealer. Or you can just build them all the way by the item order, but i dont recommend that: too timetaking to make archangel without many kills...

Mid game: is that when the teamfight starts? if so gather with your allies and unlock your weapon fo deal mass destruction! let your tank initiate, but untill then use your ulti to weaken them, when the battle starts put a combo on( E R W ) and right click the target, oh, stay helluva behind as you WILL be their target after they'll realize you cause most damage to them...

Late game: well, u should a build finished(or you're onto a rabadon) you can propably solo a turret(providing it will leave you with more than half health, shoudlnt be hard as you have speed and damage...)but BEWARE! as you can be ganked by all 5 of the enemies.
Personally best tactic my team uses is: pushing mid all to the inhib turret, i stay to harras while they take care of other lanes... alvays works, you just have to keep your distance...

Alternatives:
Even though i NEVER had to make any alternatives, you might actually swap a soulstealer for lich bane or rylai crystal scepter. but i wont recommend it, on teamfights even assists give you a boost and if you have about 8 stacks, ure good, no need to swap it... YET!

well, on this one you also decide according to your opponents, but only from level 6... also i dont recomment to give points to Q unless there's no other choice, one is just enough and that 10% extra attack speed at the beginning can kill from BAB... IF:

Wanna farm fast: by lvl 9 u should max E, this and ulti on ranged minions will give you that shiny metal a lot faster...

Anti-Tank: max the BAB of course, this and attack speed can kill them in matter of seconds(it IS true)

but im helluva sure u gonna go for farming as Kogie is item dependant...

What should i... Oh, yes... pls comment, maybe ill make it more tidy then...:P

also if you DONT believe it works, check my match history...

Enjoy the CARNAGE!!!