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.

Sismofu, once named Shinryuu, was found in the Cave some time ago by the kitsune halfbreed warrior Skie. Skie originally noticed this egg sitting in front of all the others, as if it was protecting them. He liked the egg for the flame pattern on the front of it, and quickly swiped the abandoned egg before any other dragons noticed. Some time later, a dragon was born. Skie noticed the large shield attachment on the little dragon's tail. After thinking over what name would fit perfectly, he remembered the name of the dragon from a game he had played a long time ago. The name stuck, and Shinryuu was chosen.

After a while, Skie had left the cave, and it seemed like he would never return. When the warrior had returned, he noticed that all of his dragon's names were erased! While the heinous criminal had not revealed himself, Skie took it upon himself to rename all his dragons. While Sismofu isn't seemingly as  cool of a name as the original, the dragon ended up liking the name much more.