Morlun is a vampiric being who has walked the earth for centuries. He feeds on the totems-- the core power sources of the universe. While he can feed on lesser sources such as humans and super humans, he requires a pure source to fully satiate his hunger.
In his initial appearance, Morlun drew Spider-Man, who possessed the power of a pure totem, to him. Spider-Man and Morlun battled in the streets of New York, but it was quickly revealed that Spider-Man was no match for Morlun's overwhelming powers. Before he left, Spider-Man was warned that now that Morlun had touched him, he could find him anywhere. Hoping to throw Morlun off, Spider-Man changed into his civilian clothes, but Morlun's warning struck true, and Spider-Man was found.
Having been offered earlier a place of refugee by Ezekiel, Spider-Man sought help from him. Ezekiel told Spider-Man that he was out of luck, as Morlun could now track him anywhere. There was nothing Ezekiel could do.
Facing Morlun again, Spider-Man was surprised when Ezekiel leaped to Spider-Man's rescue, battling Morlun to his apparent death. Satisfied with the life force he absorbed from Ezekiel, Morlun left to return at a later notice. Unable to find Ezekiel's body, Spider-Man noticed that in his fight with Morlun, Ezekiel had managed to shed some blood from him. Studying the blood, Spider-Man came up with a plan to defeat his enemy.
Morlun tracked Spider-Man to a nuclear power plant, where Spider-Man seemed as if he was dead, having absorbed great amounts of radiation. When Morlun went to touch Spider-Man, his hand was burned. His strength returned, Spider-Man revealed that whatever totemic powers might have been given to him by the spider, the radiation had played a role, and thus his powers were not pure. Spider-Man proceeded to deliver a sound beating to Morlun, but when Morlun was at death's door, he hesitated. Suddenly, Dex, Morlun's servant who had endured great suffering underneath his masters rule, drew a gun he had stolen and killed Morlun. Spider-Man let Dex go, and left, thinking that his nigh invincible foe was dead.
Morlun mysteriously returned months later and plagued Spider-Man by sudden and mysterious appearances, warning him that he was coming. Spider-Man, for a reason not explainable by science, was dying, and Morlun hung back to watch the causes and effects of his ailment. Finally, Morlun struck, and in a climactic battle, Morlun delivered Spider-Man the worst beating any hero had ever endured. Morlun left when the police arrived, opting for a more appropriate time to absorb Spider-Man's life force, leaving the web slinger at death's door with only one eye.
Returning soon thereafter, Morlun entered Spider-Man's room in the Emergency Ward and prepared to feast. Peter's wife, who was standing by his side, tried to stop Morlun. As it appeared he would kill Mary Jane, Spider-Man suddenly sprung to life in a ferocious display of mysterious new powers. Using stingers that sprouted from his arms, Spider-Man was seemed to eat his essence as Morlun had. Morlun apparently died, crumbling to dust. It remains to be seen whether this was a permanent death, or if the vampiric totem eater will rise again.