The Change is the physical transformation that turns a fledgling into an adult vampyre. The Change begins in a fledgling's body as soon as they are Marked; they complete the Change approximately four years after the Marking (assuming they remain within the vicinity of mature, adult vampyres), at which point they are considered fully matured. The Change is a complex thing; some fledglings die during the process. A Change-related death is explained as a fledgling's body "rejecting the Change." There is no stopping a rejected Change, and the doomed fledgling drowns in their own blood and bodily fluids. At the Tulsa House of Night, dead fledglings were resurrected as Red Fledglings. Unlike Blue Vampyres, a Red Fledgling's Change is completed upon making a clear allegiance; when a Red Fledgling chooses light or darkness, they will Change into a Red Vampyre. Stark completes the Change when he chooses Light and upon doing so pledges the Warrior's Oath to Zoey in Hunted. Dallas completes the Change when he chooses Darkness in Burned.
During the Change, many physical and psychological aspects about the fledgling change.
- Decreased sensitivity to the cold due to a lowered body temperature and transition from warm- to cold-blooded.
- Increased sensitivity to light due to the vampyre's nocturnal nature.
- The ability to "cloak oneself in night" - essentially become invisible and unheard by supernaturally blending in with the shadows.
- Enhanced senses such as heightened hearing and smell, sharpened eyesight, and night vision.
- Enhanced metabolism; inability to become inebriated.
- Increased strength, speed, agility and stamina that slowly matures and increases further as they go through the Change until becoming truly superhuman on their fourth year.
- Hair begins to lengthen and thickens.
- Hair becomes more reflective and takes on a variety of shades.
- When a fledgling completes the Change, their skin starts to "glow".
- Difficult to photograph due to mutated surface cells.
- Nails begin a growth pattern with the center of the nail bed laying down a greater thickness at a faster rate which results in sharp, pointed tips.
- Male fledglings become sterile and females stop menstruating.
- Teeth will be straighter and stronger than human dentation.
- Fledglings are able to taste foods better than a normal human due to coagulants and anticoagulants developing in their salivary glands.
- As the Change progresses, fledglings develop a bloodlust that encompasses both sexual urges and needs as well as hunger and thirst. This bloodlust is both biological and psychological.
- The ability to Imprint.
- Become more focused intellectual beings