In response to the remark on Glacial Storm Vs Frostbite as it pertains to AoE DPS:

If the enemy team is clumping up all the time and charging headlong into your tank, then yes - you'll want Glacial Storm earlier than later. But that's rarely the case - especially against intelligent opponents. I have found that the reliability of a targeted instant-cast spell outweighs 50-100 extra damage spread across a team. I found this for the same reason we focus people - a whole team brought to 1HP each is still 100% effective, which is a whole lot better than four healthy chumps and a corpse.

Thanks much! I'll certainly add more to the guide to be more specific.

Yes, people always say that Clarity is a horrible awful no good very bad choice. And always because it's all about the late-game.

This guide is about using Anivia to reach an end-game build while the rest of the players are still working on their fourth item. Its normal for me to be finishing my sixth item at 35:00. Without Clarity, I normally hit my sixth item at 45:00. In those ten minutes of tech superiority, the game is won.

Itemization on the other hand... Well that's up to the player. I'll just be removing the items outright, because this is a guide for people who understand builds and are more focused on meta-game ideas.

40 extra damage per rank on Glacial Storm is not a "small increase to its dps". That extra 40 damage adds up and starts doing massive AOE damage. This skill while very strong for its utility is equally, if not more strong for its insane damage output to multiple targets at once, absolutely not something to be ignored.

Have you ever considered maxing Frostbite first? It does almost the same damage as Flash Frost but it's targeted, instant, lower cooldown and a lot more reliable, thanks to the easy application of the chill debuff from your ULT, and the potential Flash Frost.

Comments above about the build are spot on, you absolutely need other options (e.g. Rod of Ages, Liandry's Torment) and there are some problems with the itemization ( Deathfire Grasp, very squishy, better starting options). Runes are a little bit questionable, as are the masteries.

Your reasoning against Ignite isn't really valid. It's an insanely strong spell for increasing your early game kill potential, and outclasses the meh mana sustain of Clarity, especially early on when the percent mana won't be high, and when your mana sustain will soon after be easier with Tear of the Goddess. Heal, as mentioned above, is a viable option for survivability through out the game.

Might want to cover more about gameplay and the laning phase to help players with actually using Anivia.

Haven't been on Mobafire in quite a while. I'm going to give you some feedback on your cheat sheet.

Summoner spells:
-You may want to replace Clarity with a more useful spell. Heal maybe? After your tear, your mana problems will diminish and Clarity will become useless.

Runes:
- Greater Mark of Magic Penetration is outclassed by greater mark of hybrid penetration because basic attacks are an essential part of your poke in the laning phase, and you only lose around 2 MPen.
- Greater Seal of Mana shares the same problem with Clarity. I would suggest Greater Seal of Armor.
- Greater Glyph of Scaling Cooldown Reduction doesn't seem good to me. Since Anivia is really squishy, I would prefer Greater Glyph of Magic Resist. However, I am not an Anivia player so I am not too certain about this one.

Items:
- Sapphire Crystal start does not seem optimal. Seems like a high risk kind of start. I suggest giving other options to start with.
- Deathfire Grasp is not viable on Anivia in my opinion, but then again, I am not too sure about it. However, I do believe there are better options.
-Add more options to your build, a good example would be Athene's Unholy Grail.

Masteries:
-Not a big fan of 26/0/4. I would assume 21/0/9 would be much better.

That's all for me, maybe someone else could give you feedback and tell me if I made any mistakes with mine. But I hope I helped! ^-^