Yuya Sumii

is the former leader of Team Gaim. He was originally meant to become Kamen Rider Gaim since he was offered the Sengoku Driver from Lock Dealer Sid.
==History==
Originally the leader of Team Gaim, Yuya had trouble with his team during the Inves Games when teams targeted Team Gaim when Yuya himself wasn't present. As an Inves Game user, he had his own Lockseed to call on before giving Mai Takatsukasa her own Lockseed so that she can fend for herself and the team during the Sengoku Era of the Inves Games. When Team Gaim takes a heavy hit and loses their stage, Yuya is confronted by Lock Dealer Sid, who offers him a prototype Sengoku Driver that will allow him to change the days of the Inves Games into something much more. It is presumed he was given the Pine Lockseed because it is the first Sengoku Driver given to the public as his predecessor, Takatora Kureshima used the Melon Lockseed. Yuya tells Kouta about the Sengoku Driver and tells him to meet him, but he is lured into a Crack and is drawn by the Helheim flora and eats one of the fruits, warping his mind and becoming the Byakko Inves while dropping the Sengoku Driver.
When Kouta finds Yuya's Sengoku Driver and puts it on, it also converted the premature Lockseeds into the Orange and Ichigo Lockseeds. Kouta transforms into Gaim for the first time and through the help of the Woman of the Beginning, he kills Yuya, never realizing he killed one of his close friends until much later. Yuya's death inspires Kouta to become something much more, someone to never resort to bloodshed, and as a result, Kouta puts blind trust in enemies and friends alike.
In the Soccer Cup event, Kohgane masquerades as Yuya, though he was exposed by Kouta due to the presence of a Lockseed in his possession. He soon reveals that he isn't Yuya before transforming into Armored Rider Mars and corrupting Kouta.
Yuya would appear in Redyue's illusion with the roles switched up, having Kouta as an Inves and Yuya as Gaim.
==Forms==
==Equipment==
===Devices===
*Sengoku Driver - Transformation device
*Lockseeds - Gives access to Gaim's Arms changes, depending on which lock is used
===Weapons===
*Musou Saber - Gaim's side weapon in every single one of his forms
*Arms Weapons - Weapons that come with the Arms, besides the Musou Saber:
**Daidaimaru - Gaim Orange Arms' personal weapon
==Behind the Scenes==
===Portrayal===
Yuya Sumii is portrayed by . As the Byakko Inves, he is portrayed by suit actor .
==Legend Rider Lockseeds==
*The following Legend Rider Lockseeds are styled for Gaim, as well as Kurokage, Bujin Gaim, and Kamuro:
**1 - "Waza no Ichigō, Let's go!"
**2 - "Chikara no Nigō, Let's go!"
**Riderman - "Kagakusha Met On!"
**ZX - "Jūgō Cyborg Ninja!
**Black - "Seiki Oh Black Sun!"
**Shin - "Kaizou Heishi Level 3!"
**J - "Shingeki Jumbo Formation!"
**Shocker - "Jigoku no gundan on Parade! Eeeee!"
**Great Leader - "Shihaisha of the World!"
**Shocker Rider No.1 - "Nise no Hero, Dead Go!"
**Kabuto - "Ten no Michi My Way!"
**Den-O - "Iza Climax!"
***Den-O Climax Form - "Denkamori Climax!"
**Decade - "Hakaisha on the Road!"
**Skull - "Otoko-michi Hardboiled!"
**Fourze - "Seishun Switch On!" (Despite being canonically used by Zangetsu)
**Wizard - "Shabadoobi Showtime!"
***Wizard Infinity Style - "Kirakira Infinity!"
**Gaim - "Fruits Gaim/Yoroi Musha on Parade!"
**Drive - "Hitoppashiri iza Together!"
==Appearances==
* Kamen Rider Gaim
**Episode 1: Transform! The Orange from the Sky!?
**Episode 14: The Secret of Helheim's Fruits
**Kamen Rider Gaim: Great Soccer Battle! Golden Fruits Cup!
**Episode 40: Awakening the Over Lord
==References==
==External links==
*"TV Asahi's page on the Byakko Inves"
==Navigation==
ru:Юя Сумии
Category:Deceased
Category:Gaim Characters
Category:Allies
Category:Beat Riders
Category:Gaim Riders
Category:Temporary Riders
Category:Kamen Riders
Category:First Villain
Category:Tiger Monsters