Undine Dragons are named for the water spirits with which they share territory. They have close relationships with these spirits, and are able to communicate with them. In exchange for protection and respect of their mutual freshwater homes, laid eggs are often protected by a blessing. This blessing stays with the dragon into adulthood, and with it they gain potent magical abilities. Sometimes when an Undine Dragon becomes very upset, the ground at their feet may frost over or begin to steam. They have also been observed to manipulate water directly, rerouting raindrops or creating puddles from groundwater. Undine Dragons always live near forest pools, streams, or waterfalls. Both genders take equal part in the raising of young and are very good parents—though they may not remain mated after the offspring are grown.

Dragons are highly-intelligent reptilian creatures that—from a human perspective, at least—appear to live forever. Many different varieties of dragon exist, each with their own unique qualities, habitats, and behavior. Adolescence in dragons is usually marked by the growth of a hatchling’s wings, although not all breeds of dragons grow wings and some breeds have other traits that indicate the beginning of maturation. In Galsreim, dragons and humans coexist peacefully.

Nereus, also known as the old dragon of the waterways, is rather stoic and stern especially when it comes to protecting the nearby navigable bodies of water. He's quite popular among the nymphs who reside there and as a sign of their thanks, his offspring are often blessed. Nereus himself claims that he too has been blessed as a youngster and therefore gained shape shifting powers. No one actually believes this, though, since he always says that only those who are "worthy" can witness his amazing gift.