So there are the 5 Darmanitan outside the Relic Castle. I was wondering if they were all exactly the same, or if each one had something special about them, other than Zen Mode. All help is greatly appreciated.
They're all the same; they're all at L35 when you use the RageCandyBar on them.
IVs, Nature, Gender and Shininess is random upon encounter, regardless of which one you go to. If you want something in particular, you can save before encountering one and soft-reset until you get what you want.