The Entropic Man is an ancient being of great power and the ability to decay and destroy anything that comes into contact with him. This power also appears to have a limited range but with less strength than contact.
Entropic Man was first encountered by Captain America, The Thing and Man-Thing. A religious cult led by Victorius was attempting to resurrect him with the cosmic cube. They wanted him to destroy the world through entropy. At first Jude seemed on-board with this plot, but after Captain America and the Thing argued with him, the Entropic Man said did not want a fight, and he would return when humanity begged for his gift. He did, however, plan to use his power to destroy Victorius, as a dedicated disciple (Victorius turned out to be not be so excited about this). The Man-Thing, who had the Cosmic Cube, happened to use the Cube's power at the same moment that Jude was going to eliminate Victorius, and the effect was to turn Jude and Victorius into a lump of crystal that provided life-giving radiation to the plants in the area.
Entropic Man's return would come during Paradise X. After Mar-vell (brought back in the body of a child) lead a team on a mission to destroy Death. No one was able to pass on to the next world. Reed Richards and a group of other heroes still alive would seek out The Entropic Man and beg for his return with the plan to capture him and use his power to bring death to the old an sick.
The heroes plan would be a success Jude, The Entropic Man would return to bring the gift of death to humanity. After being captured and transported to Dr. Doom's castle in Latveria Jude is confused why they begged for his return only to lock him up. Reed Richards response is that his gift must be controlled.
The Daredevil who cannot die is revealed to be none other then the devil himself Mephisto and he has other plans for Jude's gift. The heroes return to Jude to test their death formula and it works. Jude then informs the heroes that they will be truly sorry for locking him away he delivers a message of oblivion.
Mephisto then releases Jude from his captivity and he plans to begin delivering his gift starting with the unnaturally resurrected Susan Richards. After a brief battle and a mean right hook (under an invisible shield) from Reed Richards Jude is subdued and the heroes escape. Mephisto then convinces Jude to take his gift to England and the castle of King Britain. Before leaving Jude deliveries his gift everyone in Castle Doom.
Jude then goes with Mephisto to England. Jude figures out that Mephisto has his own intentions for helping him. Mephisto kills who he thinks is King Britain and gets what he wants: The Legendary Sword Excailbur. The only sword that can kill Jude so therefore control him. Jude tells Mephisto that his gift is not for someone like him to control. Mephisto is attacked by an alliance of super heros who retrieve Excailbur and we find out King Britain is alive and he proceeds to kill Mephisto. King Britian then offers Jude a deal that he can live on the island were King Arthur is buried and they will bring those who need his gift to him.
Jude The Entropic Man agrees and takes up his new role as Death.
Jude can effectively disintegrate beings through gesture or touch. He killed two normal humans with no discernible effort in this way right after he was created. He is also able to control people's minds and/or emotions, as seen when he quickly turned Captain America into a servant of entropy. Strangely, when the Thing was absorbed into his body, he was ejected as Benjamin Grimm.