My current defense team is Onyx, Frigg, Bera, Garnet & Mica. All at full talents.
I now pulled costume Kadilen and thought that adding her with 3 ninjas would make a whole lot of dodge happen.
This would be fun but would it actually make anything better?
I’ll probably level her up regardless but I would like some input anyway.
Who should I replace with her on my current team? Who should tank?
Can’t speak for ninjas but that costume Kadilen is just evil, that shimmy team dodge equals despair in my book. 
It’ll be a fun and highly annoying defense no doubt, but it’s a bit lacking in killing power since Frigg and Onyx would be your only hitters, with Bera doing her “death by a thousand minions” thing.
But hey what’s the point of this game if you don’t experiment a little and have some stupid fun sometimes right? I say go for it, see how it holds up, and report back the results if possible. I’ve certainly put out incredibly stupid defense before (like alternating R-G-B or pure yurple) just for the hell of it. Sure I end up losing more cups and revenges but hopefully my opponents appreciated the humor in it (most probably not, but oh well c’est la vie)
Btw I have Garnet Cobalt Onyx, and just pulled cKad from the most recent costume chamber. Once I get cKad to +18 in a few hours, maybe I too should try this annoying af defense just for the trollololol factor. Probably go something like Onyx-Garnet-cKad-Cobalt-cJoon/Roostley