Quote Originally Posted by Draken View Post
That depends on 10th division politics towards prisoners, actually.

For all we know of Taiki he might very well have instituted that executing a prisoner who bitches too much at you is a valid option.
Basically this. Again, please don't assume. We've already addressed that Taiki is not right in the head.

That said, it's not outright illegal and, in the case of Suzume, may have not been (I personally haven't been paying attention), but there's nothing that says outright "You can't cast Kido on prisoners," especially if it's a Bakudo. Pretty much all Hado are illegal in 10th Prisons, though.