Guardian Dragons have large shields on the end of their tails. Although the shields appear to be heavy, they are light, yet nearly unbreakable. Guardian Dragons use their tail-shields, as well as their wings, to deflect attacks and protect others. Often, they will guard the eggs and hatchlings of a nest while others are away. They are generally peaceful, and will not retaliate unless necessary. They have no need to forage or hunt, as they are fed by those they protect.

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.

Mizu Hoshi, which means water star in Japanese, is the fifth eldest within the ever growing group of dragons of DragonairBlizzard's clan. He is just another one of the Guardian dragons who do not hunt for food. Like the other Guardians, Mizu Hoshi likes to guard the eggs and hatchlings, and is very protective of his offspring. After Aki Ha had joined the group, the two soon fell in love and made a perfect couple.