As Well As The Countless Mentions He Gets In Episodes Hes Not Even In! - Tumblr Posts
Not to mention all the mentions he gets by the other villains in their episodes, whether it be that he invented something for them or they’re just poking fun at him!
Overall, Zach is definitely the main antagonist of the show and the self proclaimed leader of the villains!
I just mapped out all Wild Kratts Episodes that feature a Villain (118 in Total up to Amazin' Amazon Adventure) because I have to watch these for the Change your Mind AU and...
I crunched the Numbers, approximatley 50% (51 Episodes) of all Episodes include Zach Varmitech!
Donita Donata comes next with approx. 25% (34 Episodes), Gourmand follows close by with approx. 20% (27 Episodes) and at the end of the line is Paisley with just approx. 5% (6 Episodes) of all apperances.
The Writers definitely have a "Favourite Child"