I was wondering what happens if:

My opponent tries to recruit an equipment to his character.
While the recruit effect is on the chain, I move that character to the hidden area (or stun the character), so that he cannot be legally equipped.

Does the equipment go back to my opponent's hand, or does it go to the KO pile?

Thanks for your help.

In those cases, the target for the recruit effect has become illegal, and so the recruit effect is negated; the equipment card will be placed in the KOed pile.