|“||We’re Afterlights, the others who pass through— that’s what they call us, on account of how we glow in the dark— in the day time, too, if you look close enough.||”|
–Lief, Everlost - Chapter 4
Afterlights emit a constant light known as an afterglow, the color and intensity of which are subject to the individual's thoughts and emotions. We see on a number of occasions feelings of love manifesting themselves in a change in the color of an Afterlight's glow to lavender. Jackin' Jill also demonstrated that thinking negative thoughts can diminish the intensity of the glow, effectively masking it.
Afterlights do not feel pain and they cannot die. They don't need to eat and they don't need to breathe. Despite this, Afterlights still crave food and drink and can experience breathlessness or the rising and falling of their chest simply because of the memory of their lungs.
Nick speculated that even an explosion that separated limb from limb wouldn't end the consciousness of an Afterlight. In theory, the soul would still exist, just with its body in various locations, possibly with the Afterlight still able to feel each piece.
Bar the terrible powers of a Scar Wraith, Afterlights are eternal. The touch of a Scar Wraith can extinguish an Afterlight, expunging a soul from the universe. The only known Afterlights who have been extinguished are Squirrel and Milos.
Afterlights also don't need to sleep. While they are capable of sleep, their sleep is dreamless. Allie compared it to the unconsciousness induced by anesthesia.