He was portrayed by Hideya Tawada.
Another Shinobi was harvested from the original Kamen Rider Shinobi, Rentaro Kagura. When Sworz came to the year 2022, he derived the Shinobi Anotherwatch from Kagura, resulting in him losing his powers.
In 2019, a normal Rentaro was beaten up by some thugs after standing up for a friend. As Rentaro wished for more strength, Uhr showed up and used the Shinobi Anotherwatch to transform him into Another Shinobi. With his Another Rider powers, Another Shinobi went on a vigilante rampage where he killed the thugs who had beaten him earlier. His spree eventually led to him fighting Zi-O and Geiz.
Despite being corrupted into desiring to become king by the Anotherwatch influence, Rentaro hears Sougo's encouragements to believe in his future self, spurring Rentaro on to break his contract with the Time Jackers, allowing the Kamen Riders to obtain the Shinobi Ridewatch. White Woz then uses the Ridewatch to become Futurering Shinobi and defeat the Another Rider, freeing Rentaro.