Poison Dragon Slayer Magic is a type of Magic which allows the user to incorporate the element of poison into their body, granting them exclusive traits possessed by a Poison Dragon. The user is capable of freely producing and manipulating poison, manifested in the form of a toxic gas. Said gas seems to be "tangible", and can thus be used as an effective blunt weapon, inflicting physical damage to foes while at the same time infecting them. The poison produced by Poison Dragon Slayer Magic starts off by slowly stealing the movement from the victims' body away, before subsequently killing them. Cobra has enough faith in his Dragon Slayer abilities to claim that one touch from his Poison Dragon Slayer Magic will decay and utterly destroy everything in his path.
Being a form of Dragon Slayer Magic, this Magic allows its user to consume external sources of its element, in this case, poison, to restore their body's health and regain strength. Cobra takes advantage of the poison produced by his pet companion, Cubellios, and thus has a steady stock of poison at his disposal.
When Cobra uses his Dragon Slayer abilities, his arms become clawed and scaly, which first showcased the great corrosive power of his poison, disintegrating the sleeves of his coat merely upon activation.