The criminal known as the Death-Stalker was Phillip Wallace Sterling, the last member of an old, wealthy and prestigious family that had lived in America for centuries. It is not known why Sterling turned to crime.
He conducted his first known criminal activities under the alias of the Exterminator. In this role, Sterling was the costumed mastermind behind a series of crimes committed by the original criminals known as the Unholy Three During a clash with the costumed crime fighter Daredevil, Ape-Man succeeded in exiling Daredevil to the void with his T-ray gun. Daredevil was able to use his powers and skills to escape through a dimension warp, and tracked the Exterminator and the Unholy Three to their lair. After defeating the four, Daredevil intentionally triggered the explosion of the Exterminator's main displacement machine, hoping to end his superhero career by feigning his own death with the explosion.
At the same time, he began to steal components necessary to build a T-ray machine that would allow him to return to Earth permanently. However, Sterling was continually thwarted in this endeavor by Daredevil. He also faced a number of other heroes including Nighthawk, Dr, Strange and Iron Man.
Revealing his true identity to Daredevil, Sterling demanded a final battle. At the height of battle, however, Sterling, full of rage, miscalculated his attack and re-materialized in this dimension too soon, solidifying while passing through a tombstone. As a result, Sterling was immediately killed.
Seeking to avenge her son's death, Sterling's mother, Elizabeth Dawes Sterling, used her fortune to construct a series of death-traps within her enormous mansion. She had a large number of identical robots, all in the form of a little girl, built to lure Daredevil into the house. However, Mrs. Sterling died before Daredevil was induced into the mansion.
Sterling appears to have used his intra-dimensional powers to return . However he seems to be in a demented and somewhat confused state.