Doing a Kohaku (ConceptTopic, 15)

From Compile Worlds

Doing a Kohaku refers to when a character appears all bubbly and cheerful but is actually cold and yandere on the inside.

The concept was named, quite obviously, after Kohaku from Tsukihime, and her antics trauma had such an effect on Keiji that he now struggles to type "Koakuma" and "Koharu", almost always typing "Kohaku" by accident instead, even while consciously trying to avoid this.