Kasshin is a robotic servant of Oma Zi-O from the future and an antagonist in episodes 15 and 16 of Kamen Rider Zi-O.
Kamen Rider Zi-O
Kasshin traveled back from the year 2068 to 2019 to attack Sougo and his friends, seeking to kill Geiz. During the struggle, Tsukasa Kadoya interfered and sent Sougo 50 years in the future where he was confronted by his future counterpart.
After Sougo returns to his time and destroys his Ziku Driver so he will never become Oma Zi-O, Kasshin was reprogrammed by the Time Jackers and sent to kill Sougo to ensure Oma Zi-O never arose so they could replace him with one of their own candidates. However, as Kasshin is about to defeat Geiz, Sougo obtains another Ziku Driver from Woz and transforms into Kamen Rider Zi-O once more, thus making it possible for Oma Zi-O to rise.
Kamen Rider Zi-O: Over Quartzer
Kasshin appear as servants of the enigmatic "Wardens of Time", the Quartzer.