Sunlets are small, bird-like creatures that reside in the parallel realm of "Sundown." These creatures are born from excess of light essence, that of which is commonly present in heavily populated areas, naturally condensing itself into a living being. The Sunlets are an important member of the Sundinian ecosystem, regulating the light essence and purifying the excess essence they're made of by the end of their life. The lifespan of a Sunlet is roughly 48 hours, at they are created mainly out of what is essentially "junk," there isn't much there to sustain a lifespan that can be compared to that of a person.

However, as of recent events, Sunlets have been subject to domestication, extending their overall lifespan, but forgoing their main function of regulating the light, causing Sundown to experience periodic heat waves.