Defending the plane
He killed Faralyn just after the other planeswalker escaped to Shandalar from the Summit of the Null Moon. Sahrmal also fought Tevesh Szat, Leshrac, and Lim-Dûl the first time they assaulted the plane, sending the first two away. However, battling fellow planeswalkers had left him weak enough for Lim-Dûl to attack and apparently kill him while protecting Bani Bakur. However, his body merely disappeared as his being escaped, and so he was not actually dead, though his followers thought he was (for which they beheaded Lim-Dûl). Whilst he was not dead, he had been left weakened by Lim-Dûl's opportunistic attack, having nearly no magic left.
12 years later Lim-Dûl (who had also managed to not die) started conquering Shandalar with an army of undead in Lim-Dûl’s War. Since Sahrmal had been weakened, he had been training two adepts to take his place and face Lim-Dûl. One, who's original name is unknown, would later become known as The Guardian, the other was Azar. City after city on the plane was destroyed until, after years of war, only one city remained: Ardestan. Ardestan became the last refuge, the last protection, against the evil necromancer. The city came under siege and it was plain to all that Shandalar would soon fall to this invader. Sahrmal counselled patience, telling his students that they were not yet ready to take on the might of Lim-Dûl. But Azar, was unable to witness the suffering and inevitable fall of the city without doing something left their hidden sanctuary to defend it. Upon learning of this rash action, Sahrmal and his other apprentice went to his aid.
Azar had stolen a spell from Sahrmal designed to target the necromancer’s spirit and imprison it within his body, drawing power from it to erect a Great Barrier around Shandalar. Lim-Dûl was prepared, however, and waited nearby. He planned to transfer his spirit into Azar’s body. When Azar’s spell was complete, Lim-Dûl initiated his counter. The combined spells had the unforeseen effect of trapping both spirits within Azar’s body. The body went limp as the two souls warred for control.
Finding a successor
Saddened, Sahrmal secretly buried the body, for the Great Barrier had come into existence and it depended upon the confinement of Lim-Dûl. Meanwhile, the other student finished his training. Sahrmal, investing the last of his powers, made his pupil immortal. Then, Sahrmal proclaimed the student as his successor and vanished. The student proclaimed to the world, “I am the Guardian, immortal protector of Shandalar.”
Whether transferring the last of his powers whilst in still a weakened state killed Sahrmal is unknown as is what did happen to him if it did not.
Lim-Dûl captured him when he was protecting Bani Bakur. Lim-Dûl killed him, took control of his corpse, and used it to lay siege to Ardestan.