Basicly, the Sated devourer upgrade lets you proc any on-hit effects twice every other attack. This means that if you only auto attack, you will get Aegis protection (passive) every 3rd attack. But if you can count your passive, you can block an attack, then auto 1-2 times and use 1-2 abilities, so that you will block the next incoming attack again. This, along building a fairly tanky build, makes you almost unkillable at times.

Furthermore, Blade of The Ruined King and Wit's End will also be procced twice every other attack, for increased damage.

With this build, it is essential to be able to count Aegis Protection (passive), always keep the counter in the back of your head.
Encountering foes with Aegis Protection active, dont waiste your abilities. Use Aegis of Zeonia to stun them, but don't Q or E them yet. Auto Attack them as much you can, until they AA. Then, AA - Q- - AA, this will enable your passive again. Then do the same with your E. AA - E - AA. For increased damage and effectiviness, cancel your E almost instantly, with the 2nd AA.

An example(having stacked the devourer fully ofc.): having just taken the wraiths, you encounter a wild Lee Sin. Aegis Protection has 4 stacks (it is active). you are aware that your last auto attack did NOT proc the sated passive. You stun Lee Sin with your W, and auto attack him as much you can. He then uses his Q and auto attacks. Meanwhile, you AA - Q - AA to enable your passive. you then AA - E - AA. afterwards you do the same rotation with your Q again, then W, etc. this way you will win almost every encounter against an Attack Damage based champion.