The Slayer vowed to take the place of The Butcher, which had been slain by a trio of heroes during the Darkening of Tristram. To that end, it sought The Butcher's Cleaver. However, Andariel gave it another task, to guard the passage between Waystruck and Eastgate Keep. To that end the Slayer employed several tribes of Fallen Ones to both harass the town and do the legwork in his search for the Cleaver. In the end, it was several heroes heading for the Rogue Monastery that found the Cleaver and confronted the Slayer, destroying him.