Malebolgia created the Hellspawn to help him defeat heaven and it's armies.Cain/Cogliostro was the first person to go to Hell for committing the mortal sin of murder.
Many if not all Hellspawn are resilient and don't wish to serve under the malebolgia. As a result Malebolgia created special limitations and tests for all Hellspawn. To keep them under control, and to see who is worthy of becoming his general.
All Hellspawn are entirely composed of the substance known as Necroplasm, it is one way that the otherworldly material of Hell may manifest itself within the real world of Earth. Hellspawn however only have a limited amount of power within the Necroplasm and are forced to save their energy or go back to Hell. 9,999 units of Necroplasm are given to each Hellspawn at the start. Whether they use it or not is of their choice.
All Hellspawn are given a special symbiotic suit that feeds of their necroplasmic bodies for substance. The suit itself is also Necroplasm based and is fused to the Hellspawn's nervous system. In return for the Necroplasm the suit gives the hellspawn great protection and will protect it's host at all costs allowing the user to use his own body as a living weapon.
The Hellspawn Al Simmons was endowed with a much more powerful suit from the Leetha class. K-7 Leetha is believed to be the most powerful of the Hellspawn suits and even goes through it's different stages of evolution at a much faster rage than other suits.
Although Malebolgia created the bulk of Hellspawn there have been others...
Bairn- Bairn is a Hellspawn created in an alternate universe by an aquatic deity who utilizes him to kill gods.
Nyx- Although not technically a Hellspawn she stole Spawn's suit and powers taking his place in order to enter Hell.
Necro Cop- The first and only known man-made Hellspawn. It was destroyed in the sewers of France by Spawn.
Daniel Llanso- Created in a distant future by Phlegethonyarre the ruler of Hell at the time.