Kappa are a species of youkai who have lived among humans in disguise since the dawn of the human age on planet Earth, Kappa seem to think they're on good terms with humans, but some of the folklore by humans handed down over the generations suggest that humans think otherwise.
All kappas are geniuses at the things they care about, and many have gone to become great scientists and engineers.

A smalll group of them followed the human expedition to New Eden and hence have co-existed with their human counterparts ever since, and are the major rebuilders that have helped all the 4 factions to rebuild their lost technologies.

Recently a group of kappas lead by Nitori Kawashiro formed a neutral corporation, to rally all kappas in New Eden in the hope that one day kappas will form a new government on their own, and be finally be fully recognise as an equal to humans rather than continue to live in the human's shadow regardless of their contributions.