Soichi Isurugi (石動 惣一 Isurugi Sōichi) is the father of Misora Isurugi, the owner of the café nascita and one of the main villains in Kamen Rider Build. Upon finding the amnesiac Sento Kiryu, he gave him a place to stay in the basement of nascita.
Along with his daughter, Soichi made a debut as one of Marika Kato's followers to help Milinda Brantinni and her friends in a raging war against the soldiers of Gjallarhorn.
After the deaths of Kain and Thornheart, he and the heroes continued to live a life with his friends in Mars. Suddenly, he and the people were visited by the Symphogear heroines and their friends for the first time. During the meeting, he and the gang decided to discuss about the future deaths of Rustal Elion and the rest of Lord Prozen's minions as well.
After the meeting was finished, he and the heroes left their homeplanet Mars, thus leaving their families and their homes behind. While continuing to escort Futaba Ichinose and Chitose Karasuma, he and his friends were confronted by the people of the Knights of Gjallarhorn. Suddenly, he and the heroes decided to trick them by sending Flint Lockwood and Steve the Monkey to Knights of Gjallarhorn. While continuing their journey, he and the heroes were attacked and fought by Transylvanian Business led by Wataru Kurenai. After the fight was finished, he and the rest of our heroes convinced them to realize the errors; so that, he and the heroes must work together to reconcile peace between humans and countless species.
After the defeat of the Bruters and the death of Yan Baihu, he and his friends continued their journey to earth.
Allies and Enemies
Allies: Hibiki Tachibana, Tsubasa Kazanari, Chris Yukine, Maria Cadenzavna Eve, Shirabe Tsukuyomi, Kirika Akatsuki, Miku Kohinata, Souji Tendou/Kamen Rider Kabuto, Arata Kagami/Kamen Rider Gatack, Ruuji Familon, Arashi (Zoids), Midori, Heero Yuy, Kira Yamato, Setsuna F. Seiei, Bugs Bunny, Sento Kiryu/Kamen Rider Build, Milinda Brantini, Dominic Toretto, Greg Heffley, Tsubomi Kido, Wade Owen Watts, Shouya Ishida, Hei (Darker than Black), Ryuga Banjou/Kamen Rider Cross-Z, Misora Isurugi, Sawa Takigawa, Eiji Hino/Kamen Rider OOO, Professor Kukui, Professor Burnet, Kouta Kazuraba/Kamen Rider Gaim, Kaito Kumon/Kamen Rider Baron, Mitsuzane Kureshima/Kamen Rider Ryugen, Takatora Kureshima/Kamen Rider Zangetsu/Zangetsu Shin, Suzuka Kamiki, Gas-House Gorillas, Kazumi Sawatari/Kamen Rider Grease, He Jin, Hyde Kido, Bastion Misawa, Horrid Henry, Mirei Mikagura, Etemon, Volcamon, Yūna Yūki, Mimori Tōgō, Fu Inubouzaki, Itsuki Inubouzaki, Karin Miyoshi, Sonoko Nogi, Hiroki Nagase, Masaru Ooyama/Akaba, Syuuya Aikawa/Aoba, Syoukichi Mihara/Kiba, Futaba Ichinose, Chitose Karasuma, Kenzo Tenma, Kudelia Aina Bernstein, Atra Mixta, Wataru Kurenai/Kamen Rider Kiva, Kivat-bat the 3rd, Kate Green, Gentoku Himuro/Night Rogue/Kamen Rider Rogue, Rinna Sawagami, Nariaki Utsumi, Akari Tsukimura, Leena Toros, Aila Jyrkiainen, Mitsuya Majime, Hester Shaw, Kouhei Araki, Jiro, Ramon, Riki, Leo Conrad, Sally Land, Seraphimon, Cherubimon (Good), Ophanimon, Guardian Eatos
Enemies: Gunther Prozen, Thaddeus Valentine, Hajime Busuzima, Thornheart (deceased; killed by Milinda Brantini), Dr. Ellie Staple, Kain (RESTOL Special Rescue Squad) (deceased), Flinty McCallahan (deceased), Greta Hideg, Matori, Dr. Zager, Gozu (Pokemon), Mikie Okamine, Masakuni Mido, Jail Scaglietti, Gabby Jay, Alva,Kuroto Dan/Kamen Rider Genm (formerly), Rustal Elion, Carta Issue, Iok Kujan, Gallus Bauduin, Elek Falk, Iznario Fareed, Nemo Baklazan, Julieta Juris, Wolf Rocky, Knight Unryuji (formerly), Shia Kijima, Wilfrid Kijima, Saga Adou, Swartz, Uhr, Ora, Tid, Great New Empire