Kiba is a member of the Hokuto Three Crows and a supporting protagonist in Kamen Rider Build. He originally took part in the Hokuto invasion of Touto but later defected to Team Build along with his boss Kazumi Sawatari after Seito occupied Hokuto.
Syoukichi Mihara was originally a worker at Kazumi Sawatari's farm along with Masaru Ooyama and Syuuya Aikawa. When the Skywall Disaster made Kazumi's land infertile, Kazumi used his savings to continue providing for the three and their families. Eventually, after the Hokuto government made a pact with Faust, Kazumi volunteered himself for the Faust organization's experiments so he could continue to support his workers, becoming Kamen Rider Grease and a soldier of the Hokuto government.
Out of loyalty, Syoukichi, Masaru and Syuuya joined the Hokuto military as well and volunteered themselves to be converted into Hard Smash to aid Sawatari as the Hokuto Three Crows. Becoming the Owl Hard Smash, Syuuya was code-named "Kiba".
After Prime Minister Yoshiko Tajimi declared war on Touto, Aoba and the other Crows were sent in to spearhead the invasion alongside Kazumi Sawatari/Kamen Rider Grease. However, after Hokuto sent in all their troops to invade Touto, Seito took the opportunity to invade and occupy Hokuto, easily conquering the country. Kiba was later beaten and held hostage by the Washio brothers to lure out Kazumi. He was freed by Akaba while Grease fought off the Washio brothers, though was later wounded fatally when he sacrificed himself to protect Kazumi from one of their attacks. As he lay dying, Kiba gave Kazumi his dog tag and told him that he would be watching over him with Aoba before disintegrating into yellow smoke.
Return as a clone
A clone of Akaba along with clones of the other Hokuto Three Crows were later created by Evolt from his DNA and sent after the four Kamen Riders as they stormed the Pandora Tower. Grease opted to stay behind to fight them, telling his fellow Riders to go on ahead without him. After transforming into Grease Blizzard, Kazumi managed to defeat and destroy all three clones though he died soon after as a side affect of transforming with Blizzard Knuckle.
In the new world created by merging the World of Build into the main Kamen Rider world, Syoukichi as well as Masaru and Syuuya was still a worker at Kazumi's farm. He was seen eating at the nascita cafe with Kazumi and his coworkers and had to catch his boss when he fainted after falling in love with Misora at first sight.
He later assisted Kazumi in his fight against the Downfall terrorist organization.
- Kiba means "Yellow Wings" in Japanese. Not to be confused with Kiba (牙) which means fangs.
Kamen Rider X
Kamen Rider Amazon
Kamen Rider Super-1
Kamen Rider ZX
Kamen Rider Black/RX
Kamen Rider Kuuga