Coarb

A coarb, from the Old Irish comarbae (Modern Irish comharba, Latin: hērēs[1]), meaning "heir" or "successor",[2] was a distinctive office of the medieval church among the Gaels of Ireland and Scotland. In this period coarb appears interchangeable with "erenach", denoting the episcopally nominated lay guardian of a parish church and headman of the family in hereditary occupation of church lands. The coarb, however, often had charge of a church which had held comparatively high rank in pre‐Norman Ireland, or one still possessed of relatively extensive termon lands.[3]

Also as per this article "... such lucrative monastic offices as “coarb” (comarbae “heir” to a saint) or “erenach” (airchinnech “superior”), otherwise transmitted by natural or nepotic descent within ecclesiastical families, which were often the politically displaced branches of royal dynasties"