stray swallow
So Tempest, Oathkeeper, Orb of Enlightenment, Magnify, Prophecy, Oblivion Crown (I havent considered what order to buy them I'm just looking at full build)
You'd have so much attack speed I'd call the general gameplan Q, auto, E, auto, auto
You'd get one Oathkeeper proc (due to the item's internal CD), one magnify, and three prophecy procs for a total of 110% extra scaling, the passive would do 30%, and his abilities would do 80% and 70%. Total is 290%.
Total magic power is 513, for a total of ~1500 just from scaling.
You'd get ~300 damage from physical scaling (all characters get some physical power based on level)
You'd deal 560 flat damage from abilities, autos and prophecy.
Total of 2360 damage from just one combo which can be fully completed while the target is stunned. Its unlikely to one shot due to a lack of pen, but it's pretty damn close.
Also this doesn't include items with a longer cooldown i.e. Oblivion Crown passive and Tempest.
stoic dove
half wasp