Aria dragons are a brightly-colored and sprightly breed, perhaps most adored for their lyric calls. Their song-like melodies fill the areas they inhabit; their coos resemble those of birds, only more elegant and refined. They have fairly strong magical capabilities, but tend to reserve these strengths for last-minute defense, choosing to live their lives in simple peace. Arias, sticking to the tropics, typically live quite far from human settlements, giving rise to the previously held belief that they had gone extinct.

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.

Kazuichi Soda is forever tinkering with various metallic items. His title translates to 'mechanic'—he's the Ultimate Mechanic at Hope's Peak. His aim is to create contraptions that can improve the world: ones powered manually, others by the elements such as water and fire or both for that matter, and ones that can work if an Electric dragon is present. Perpetual motion is a goal that he aims to reach: so far, basic friction was resulted in even mana-powered machines to eventually stop.

Once a meek and bullied student, Kazuichi vowed to change his demeanour the minute he was accepted into Hope's Peak. His timid nature is still very obvious though—anything that upsets him is usually met with an overblown reaction, a high-pitched screech and words scrambling to explicitly state how much he does not like this. He also has a tendency to just present himself rather obnoxiously; the dragon he loves, Sonia Nevermind, avoids him whenever possible, as he flirts with her any chance he gets.