He is the old man of the Ichinose's clan, who also acts as a butler for Nagi Ichinose. When Nagi was younger, she saw Ojii-san struck by lightning for four times, which resulting in Nagi's fears of lightning.
He is also willing to do just anything for Nagi. For example at Tokiwadai Land, he puts on the Pocky costume so that he could observed Nagi from close distance. [1]
