Vapor is the result of a series of experiments derived from the need to exterminate a virus. Although she is only physically two years of age, she has been imbued with the knowledge of an older person. Though still immature and playful, she is learning to take her job seriously.

Vapor has the ability to control water; she has a special bladder that contains water that can be emitted through her fur to create mist, though she can also pull water from other sources. Vapor is sustained purely by water and does not consume food; she has no sense of taste. Her eyes do not have a a tapetum lucidum (reflective eye lens), hence aiding her in her ability to hide in the mist she produces. Her specialty weapon is an ice sword; with enough experience, she is able to create superheated ice.