Spawn is technically dead, and effects that normally work on living creatures have little or no effect on him. His necroplasmic armor grants him great resistance to injury and access to a reservoir of power that he can use to heal damage to his body, fly, teleport across distances, project bolts of glowing green hellfire and a vast amount of others. This reservoir is limited, and if he drains it, he will be pulled back into Hell permanently.
As a former government-sponsored assassin, Spawn is a master of many forms of armed and unarmed combat and is well-versed in conventional and unconventional warfare. In his hands, any object can become a weapon, although the chains around his waist and his gigantic red cloak are his primary wapons.