Ghost Soldier is created by Aaron Kuder and Greg Pak.
Despite having multiple appearances little is known about its origins, but in Action Comics #28 he says his name is Leonard Sawyer.
Major Story Arcs
Underworld & Unbound
Ghost Soldier was sent to the city of Calles de Los Olvidados in Venezuela to track and take down Superman,his powers were effective to the point of almost mortally wound him and despite that Superman managed to get rid of him and took the electric dragon to the Fortress of Solitude. Meanwhile Ghost Soldier follows Lana Lang and her staff to a cave that goes to the underground and discovers an entire civilization comprised of beings never seen before and then is ordered to investigate them to find out if they can be a threat to the world.
Meanwhile Superman discovers that the inhabitants steal life force of some creatures to provide energy for the whole kingdom and then decides to save them, but is interrupted by Ghost Soldier that warns their actions could cause an incident on a global scale,but he chooses to ignore and save the creatures anyway. In retaliation Kokya releases an army of stone robots to stop them. After destroying the stone army they return to the surface with the little creatures, who are not accustomed to sunlight and end up becoming murderous beasts.
Leonard Sawyer stabs Superman from behind and kill the small creatures. Recently recovered an angry Superman, takes advantage that he is in solid state and uses his freeze breath, then remove his helmet to find out who's calling the shots and goes after them. Ghost Soldier ended up being thrown against the Tower Command's building.
Ghost Soldier traveled to the Phantom Zone and eventually found Wonder Woman and Batman fighting Mongul, to save them makes it intangible and teleports them to a distant location. Then Wonder Woman uses the lasso of truth then he reveals that he knew that the Tower was responsible by releasing Doomsday, so he wanted to redeem himself by helping them. Not far away they found a strange machinery that's tapping power from a rift in the Phantom Zone and they end up being attacked by the Phantom King. Ghost Soldier tries to make it intangible,but ended being defeated
Phantom King proved to be responsible for releasing Doomsday from Phantom Zone's forbidden zones areas, as well as the creator of the technology that allowed Harrow's Ghost Army to manifest themselves. After a brief battle they manage to defeat it with the help of Mongul and take him to the Fortress of Solitude. Soon after Leonard is seen with the Ghost Army assaulting Brainiac's drones,however the attack is unsuccessful and the army is assimilated by them
Powers & Abilities
Leonard Sawyer is a ghost of a soldier and therefore it has the same abilities of other ghosts.
Phasing/Intagibility: Ghost Soldier has the ability to become tangible or intangible at will,as well as can make objects and people tangible or intangible,and also is able to merge people with objects.
Using a simple steel knife he was able to split Superman's molecules and short circuited his armor.
Flight: He naturally able to fly surrounded by a kind of blue flame, which is probably etheric energy. He can modify this energy in a sort of disk so it can levitate in the air, while in a solid state.
Teleportation: Ghost Soldier is able to teleport at large distances and even to other dimensions as the Phantom Zone.