Subaru's father. Opposes his son's interest in robots and wants him to join him as a fisherman after graduation from high school.

2019, Divergence Ratio 1.048596 (Steins Gate worldline). The near future, where a device popularly called the PokeCom, packaged with PhoneDroid OS, spreads, bringing the Augmented Reality world close to existence. 
Central Tanegashima High School's Robot Research Club is in danger of losing its club status. Kaito Yashio, one of only two members, is only obsessed with robot fighting games, showing no interest in the Robo Club even in this situation. The reckless, useless club head, Akiho Senomiya, aims to complete a giant robot, struggling hard to avoid losing the club's status. 
Then, one day, Kaito discovers the A.R. annotation that becomes the Kimijima Report. Written in that report is the indictment of someone named Kou Kimijima's conspiracy involving the world. 
(Source: VNdb)

The story detailing the past of Senomiya Misaki, elder sister to the Robotics;Notes heroine Senomiya Akiho.

An alternate story of "Robotics Notes" centering on Frau's route. 
 
In 2019, childhood friends Yashio Kaito and Senomiya Akiho are together in their high school's robotics club, but it is in danger of being abolished. Akiho wants to preserve the club, as she feels like it is her last link to her older sister, a roboticist. Akiho has only Kaito to rely on, but he's more interested in the game "Kill Ballad Online." It turns out, though, that Kaito's obsession with Kill Ballad may come in handy for their robotics club, and there are other allies they'll meet along the way!

Hiromu Hidaka