Devourer is stronger on Shyvana than any other champion in the game (well damage wise). She has so many AA procs in her kit it makes my head spin thinking about it, not to mention she benefits greatly from the attack speed and of course
. I'm a jungler main and have been playing Shyvana for a long time and she has never been stronger than she is right now. I've done some crazy things with devourer Shyvana, including recently standing in the middle of a fiddlesticks ult, their mid laner and adc 1v3 and literally 2 shotting the mid laner and adc and I didn't 2 shot Fidds because he had Zhonyas. All of them were quite fed and I was actually behind...but once you get sated you can do some crazy damage, even if they are massively fed.
I've played pretty much everything there is to be played with sated and not much comes even close to Shyvana. And the most horrible thing about Devourer Shyvana? You only need 2 items. The rest you can build pure tank, you'll still 2 shot carries.
(Btw, Devourer Tahm is an absolute monster as well. Double hit works with his passive, so the more health you stack the more damage you do.)