Having no friends in elementary school, and believing that "humans aren’t worth trusting", Ulillillia began inventing a coterie of imaginary friends in January 1990. The number of imaginary friends grew to twelve before dwindling to three in the late 1990s as he grew more trusting of other people. In 1999 Ulillillia started calling his remaining imaginary friends "guardian spirits".
The three remaining "spirits", Speed, Sliat and Knuckles, appear in "The Story of the Wonderful Adventure". Knuckles appears as the protagonist of Ulillillia's novel The Legend of the 10 Elemental Masters, with Speed playing a supporting role.
- Speed—A 23-inch-tall humanoid with sea-green fur and dog ears. As one might expect from the name, he is "[e]xtremely fast". Originally named "Cinos" (which is "Sonic" backwards), the character's name was changed due to people confusing him with Sonic the Hedgehog, although Speed's creation supposedly predates that of the Sega character.
- Sliat—Another furry humanoid. Very "funny" but "weak in power and abilities". While none of the imaginary friends have human genders, Sliat is alone in being referred to with female pronouns.
- Knuckles—A 25-inch-tall humanoid with orchid-colored fur and disproportionately large hands. Created in 1996. He is best known as the protagonist of The Legend of the 10 Elemental Masters.
- Quarrex—The last of the canonical twelve and the only one of the friends who is an ordinary human being. Described as a five-foot-seven African-American male with curly hair. Ulillillia remembers little about him.
- Enemy—An antagonist character about whom very little is known, even by Ulillillia himself. He was defeated by Cinos/Speed and taken out of "existance" [sic].