Kaito Kumon (駆紋 戒斗 Kumon Kaito) is the deuteragonist of Kamen Rider Gaim. He is the founder and former leader of Team Baron. He was Kamen Rider Baron (仮面ライダーバロンKamen Raidā Baron), receiving a Sengoku Driver from Sid and later upgrading his power to the Genesis Driver. After retaliating against Ryoma Sengoku, his Genesis Driver was destroyed, leaving him no choice but to use his Sengoku Driver again.
Kaito Kumon made a first appearance as one of Marika Kato's followers in Mars. He went on a practice training with Milinda Brantini and her friends as well.
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, Kouta and the heroes left their homeplanet Mars, thus leaving their families and their homes behind. While continuing to escort Futaba Ichinose, Norimichi Shimada, and Chitose Karasuma, he and his friends were confronted by the people of the Knights of Gjallarhorn. However, he and the heroes managed to trick them by sending Flint Lockwood and Steve to KOG. Then, he and the heroes met the Transylvanian Business for the first time.
After the defeats of the Bruters and the
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, Marika Kato, 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, Soichi Isurugi, Misora Isurugi, Sawa Takigawa, Eiji Hino/Kamen Rider OOO, Professor Kukui, Professor Burnet, Kouta Kazuraba/Kamen Rider Gaim, 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, 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, Futaba Ichinose, Chitose Karasuma, Kenzo Tenma, Kudelia Aina Bernstein, Atra Mixta, Leo Conrad, Sally Land, Seraphimon, Cherubimon (Good), Ophanimon, Guardian Eatos, Carly Carmine, Naoto Kurogane, Hina Amano, Yugi Muto/Yami Yugi (Atem), Aichi Sendou, Ruko Kominato, Tama, Dan Bashin, Gao Mikado, Ayato Kamina, Kuroto Dan/Kamen Rider Genm, Knight Unryuji, Rona Tsunomori, Rei Kiriyama, Yuinshiel Asteria, Rena Asteria, Hazuki Kagimura, Touma Kamiyama/Kamen Rider Saber, Rintaro Shindo/Kamen Rider Blaze, Kento Fukamiya/Kamen Rider Espada, Ren Akamichi/Kamen Rider Kenzan, Ryo Ogami/Kamen Rider Buster, Grizzly Bear, Panda Bear, Ice Bear
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 (deceased), Matori, Dr. Zager (deceased), Gozu (Pokemon), Mikie Okamine (deceased), Masakuni Mido, Jail Scaglietti (deceased), 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 (deceased), Wolf Rocky, Knight Unryuji (formerly), Shia Kijima, Wilfrid Kijima, Saga Adou, Swartz (deceased), Uhr (deceased), Ora (deceased), Tid (deceased), Great New Empire