John Manners died in 1402, probably leaving the castle to his son, Robert, who in turn left the property to his own son, another John Manners. John was involved in a long-running feud with the neighbouring Heron family, who owned the neighbouring Ford Castle, and on 20 January 1428 there was a fight between the two sides outside Etal Castle, in which William Heron died. The precise events are unclear and formed the basis of a subsequent lawsuit, but John argued that William had assaulted the castle, during which attack he had died, and that John had no direct involvement in his death. William's widow blamed John and his eldest son, also called John, for William's death and demanded compensation. After arbitration by the Church, eventually John agreed to pay for 500 masses for William's soul, and to give 250 marks to his widow.