coadjutor

noun2

1. •
   An assistant or helper.

   • Then have the lady patronesses and their active coadjutors, whether noble or ignoble, all the work of beating up for recruits to go over again. — 1842
2. •
   An assistant to a bishop.

   • When old age rendered any Bishop unable to perform his duties, the first example of which occurs AD 211, when Alexander became coadjutor to Narcissus at Jerusalem — 1842