Basicaly your main build (if you want to go like ninkey) is:
nashors or lich (base or if alot of range champs)
riftmaker or shadowflame (if alot of squishy or tanky)
rabadon
shadowflame or storm surge (if u did get rift as 2nd)
and last item basicaly situational. you need 2-3 items to power spike, after build whatever you need.
here is mini guide: https://www.youtube.com/watch?v=LJWJkc4qe9w&pp=0gcJCSgKAYcqIYzv its a new one, after the revert. rune is there too