Klaus Goldstein is the first romanceable character from Season 1 and second to Season 6, respectively: Main Route I, its Sequel and Main Route II.

Klaus is the second son of Walter Goldstein, a famous wizard known for his Magical Tools creations. Klaus is a certified Elite Magic Knight and has researched dark magic in the past to assist with its eradication

Klaus is characterized by single-minded intensity, as well as a harsh, unforgiving, strict demeanor though can be kind.