Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
This build gives you insane nuke. If you are careful you will easily get 900+ AP. The reason for Ghost is to keep your stacks in soulstealer and at some points its great for getting a kill. Ignite is more or less for early kills however it can be that extra dmg to kill a runner. With this build you should always be solo lane and gank as much as possible when you get Soulstealer but remember to check minimap often if ppl don't say miss because loosing stacks is the worst that can happen.
Anivia is hard to last hit with normal attacks so get Tear of Goddess asap so you can use spells on creeps. The reason for 3 Archangels is the insane it will give and in turn 9% of that mana will be converted to AP.
I use Ability Penetration boots in this build but if you are against a team with loads of disables and magic dmg go for Mercery Treads instead.
You might want a Rod of Ages if you feel it will be a long match but usually I prefer to get 3 Archangels.
When you have maxed Flashfrost and Frostbite you should focus mostly on team ganks because at this point you will be very fragile but dangerous since you would kill fragile champions with ulti + flashfrost and flashfrost + frostbite will kill most other champions.
This is not your main spell use it to harass and initiate with the stun.
One of the best spells in game, if you can land it right however if you can't it will usually be the biggest teamkill spell of all.
Your biggest nuke and main spell. Combo it with FF and you will do some seriously damage. Remember to always have the chill effect up when you use it.
If you can combine Glacial Storm with your other spells everything but a tank is dead. However it is really mana consuming early on so be careful how you use it. Late game this + FF is really good for farming.
Tips n Tricks
Using crystallize to force the enemy into your FF and Ulti is a really good way to get a kill.
Crystallize can be used to seperate enemies and to save your friends/yourself.
FF, Crystallize and the Ulti is a good for escapeing stun, block and slow.
When getting the golem buff the easiest way to do it is to block him with Crystallize, have ulti up and use FF + Frosbite. If you have been doing right and have about 15stacks mid game this will most likely kill the golem if not just do a few autoattacks and another Frosbite.