Hey, there, man! I've saw your guide and I loved you idea of Aatrox with Youmuu's Ghostblade and Black Cleaver. His main Problem is his lack of movement speed, though he has a slow and gap closer, and you fixed it and added some cooldown.
But I've wanted to ask you things I think it is lacking in your guide:

- Aatrox is far for been considered an ADC and except for your Boot choice and Black Cleaver, that makes him a bit tanky, I saw only damage itens in this guide. What kind of defenses would you build up?

- Why should we build Last Whisper if we already have % armour penetration with Black Cleaver? Even if we were facing a very tanky team, I don't think there is any need for both itens on Aatrox. More over, even if it was for the AD, Aatrox received a little buff on his Blood Well in patch 7.5. Thanks to his Blood Rush the extra AD give us space for armor, health and MR.

- What would you use for Lifesteal? His Blood Thirst now give a great sustain, but only happens every 3 attacks, which makes me think he needs lifesteal. Why not Ravenous Hydra? Gives a good lifesteal and it's passive helps him on clearing monsters, creeps and enemies.

- Last, but not less importantly, your build is great, but it is a bit expensive. Guinsoo's Rageblade gives everything that adds up to Aatrox needs, but I wouldn't considerer building as a 4th item, maybe as a 5th ou 6th. I believe that Aatrox will need some resistance or lifesteal as the game go, though you hindered this problem with the health given by Black Cleaver. Also, not always we would build it, we might find other options on the way as the game goes.

I really liked your build, but you should improve it a bit more with tips and how to play.
I am more like a 4fun player and prefer ARAM, but I know that most people here on Mobafire are from silver to gold (even platinum), and you are a MASTER player, you do have the knowledge that would improve everyone's game here.