yeah, as before mentioned (just above) Last Whisper was changed. you might want to change it for Black Cleaver or something, as that pretty much gives the same things as Last Whisper did.
But it gives more of it, and accordingly is more expensive, so you might want to wait with it until a later time in the build :)
just my suggestion :)

Feelt i needed to tell you, after the last nerf/patch Last whisper was one of many items that got changed, and now its 40 dmg and 40 armor penetration ;)

Amazing build. I wanted try out Pantheon and i tried your build and its perfect. Usually when i use someone elses build i would normally change something that fits my playing style. But this one really hit the nail on the head. Good work!!!!

+1

7-0-7 first game (:

Great build went 22/1/1 first game ever playing panth. Keep up the good work

i'm pretty sure last whisper doesn't stack with his abilities. I'd replace that.

Awesome build. I pwn. E useless xDDDD. I can beat on tower vs full hp.

Best pan build. rated up

5-0-5 with this build. My FIRST time playin pantheon. I dig it so far :)

Great build you have there! I usually don't play phant, but this builds make me wanna try him out! And i just wanted to mention, Shen is a very good laner with phant! As playing shen,I have never lost a game laning with phanteon :D

Wow, this build pwns...I usually suck with Pantheon an thought an attack speed Pantheon would be just...well, yuck. But dang, I went 15/13/20 in a 5v5. +1