At the start of Episode 9 - Daughter of the Ebisugawas: Kaisei when Yasaburō is having a monologue about how he was arranged to marry Kaisei before her father called off the marriage after Yasaburō's father died, he says,
By the way, my cousin's weird, un-tanuki-like name "Kaisei", was something my dad came up with.
What makes Kaisei's name "un-tanuki-like" in comparison to the other characters?