This Is very very good Build

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I was thinking that ori could be build like this and i was trying to make her a build and then i search the build here and yup.. not the only one lol ORI ASPD FTW!

Nice job with the build. Most guides go just AP. I like the way this implements her passive.

Not as good as other builds.

Omg!This is not a built for Orianna!

Omg!This is not a built for Orianna!

Totally love the build.
Especially items that synergies with her passive.

i jsut imagined the smae build thx for doing it before me, now i can follow it :D

This is pretty much the build I was thinking of when I first saw Oriana, but I don't own her and I've never tried it. Anyway, think you should consider something in the line of Rod of Ages, Sylai's, Zhonya's Hourglass or Archangels Staff to boost your AP, in place of Madred's. Not saying you should never build the Bloodrazors(just see them as a situational thing for when facing tanky opponents), but you would certainly make a noticeable difference to your AP, and advantage from Rabadon's passive(a free 20-40 AP can't hurt).
An early Tear of the Goddess really wouldn't work that badly on her IMO, as Command: Attack has a reasonable CD, and your building CDR early, so you shouldn't find it that hard to stack. What's more, you could easily get either Manamune or Archangel's in this build, so it would be a versatiel option. Anyway, completely up to you, but I think I'd like to have that extra AP late game, as it's going to make you much more threatening. Another option might be Hextech Gunblade, which would certainly provide some nice sustain.

The other thing is that you really need to include Surge in the Summoner Spell section: whether you like it or not, it's a logical choice which provides the 2 stats your focussing on(AS and AP), so it at least deserves an honourable mention.

Thank you guys again for the continued support. I will always use your ideas to help with the build and also @Cubb1313 I will definitely consider using frozen mallet, I have thought so for a while, but Rabadon's Deathcap is to increase some damage on her passive. I will add the frozen mallet concept and see how it works out as well. And thanks again =]

Finally voting works, I would've come to upvote yesterday but no matter how much I hit +1 it didn't work :( But luckily it works now so good job, I played with your guide and did quite well. It was so much fun I'm going to continue playing more. +1