Joab (David's compatriot living at the time of United Monarchy)

Joab was David's nephew and the commander of his army for most of his reign, fiercely loyal to David's interests even when that meant acting against David's explicit wishes, as when he had Absalom killed against David's direct order to spare him. Joab also arranged Uriah's death in battle at David's request to cover up David's affair with Bathsheba, and he murdered two rival commanders, Abner and Amasa, in acts of personal vengeance disguised as reconciliation. David never forgave him for Absalom's death and left instructions for Solomon to have Joab executed, which Solomon carried out even after Joab fled to the altar for sanctuary.