They are "Neo Nectar"'s bioroids born from the flowers of wisteria. Due to the structure of the plant, multiple bioroids can be born simultaneously from a branch of wisteria, and many Wisteria Knights born in the same generation share identical forms and sounds.
For unknown reasons, the flowers of wisteria have poor mana absorption rate. No bioroids have been sprouted from wisteria until the emergence of "Master Wisteria", a powerful individual of "Neo Nectar" called the Deep Green Lord.
Nevertheless, after "Invasion Great War", the experiment of anchoring mana onto wisteria flowers attained success abruptly, possibly because of the great war's influence on the air, the land and the nature of spirits. After that, many bioroids have been born from wisteria without the slightest failure.
Master Wisteria is calm and composed, but he loves the nation passionately, with the resolution to protect it with his life. The Wisteria Knights are belligerent and aggressive, but they truly hold the ideals to protect the nation. Born from the same species of flower, the same origin, they are similar in nature.