He was first summoned when Rōzu was in the academy then he was summoned from then on.
Kakeru was serious and sometime sarcastic. He showed great respect to his summoner and Itachi Uchiha by calling them Rōzu-san and Itachi-shi or “Ms. Rose” and “Mr. Itachi” and in return, they called him Karu. He liked the name Karu so much that he insisted to be called that and only that.