Kyun's grandfather has dimentia and mistakes Kyun for his mother. He once took care of Kyun during her childhood and with her ill father in the past. He holds a special place in Kyun's heart and is a good man who must've had been distraught with his son's passing. Over the years as he cared for Kyun he gets dementia and, in a switch of roles between caretaker and the one being taken care of, he has to be taken care of by Kyun.

A whithered and elderly voice is needed for him. Due to his dementia, he has reverted back to the mind of a child. So his lines will be comprised of "typical childlike lines."