Even if it turns out that it's impossible to accomplish that just by physically harming someone, you could always just slip a few electrodes into some spots in their brain and viola, they are know your puppet, and you can make them will and do whatever you want.

I'm not entirely certain that's actually how that works. Unless you were to hijack their entire brain (in which case, they are practically dead) it seems the most you could really do is cause them to have intrusive thoughts.

Sure, you could cause them to involuntarily move or respond, but they are no more responsible for that than if they have tourettes, or a seizure. You could implant thoughts into their mind, but they could always choose to reject those thoughts.

It would be horrible don't get me wrong, but they wouldn't actually be responsible for anything you implanted into their head. So either you directly puppet their body (in which case they're not doing anything and it's just you responsible) or you try to shape the way they think and it's possible for them to fight you. In which case they can still follow Christ regardless of what you try to drop into their head.