Yaiba of Darkness, nicknamed "The Paper Crane Ninja", is the teritiary antagonist in GoGo Sentai Boukenger. He believes that darkness is the superior force in existence and uses two ninja swords that can be combined into a double bladed naginata.
Though he wears a facemask, it opens up to a terrifying monster-like face when he is about to kill, performing the "1000 Paper Crane Dark Blizzard" that summons a hail of deadly colorful origami cranes that repeatedly strike and slash the enemy. Yaiba used that attack to slay Masumi Inou's abusive excavation group when Masumi himself was little, and since then a rivalry/grudge has grown between them.
Yaiba also revealed to Masumi that he let him live that day because of the darkness in Masumi's heart when he used the excavation group as a shield. After being labeled a traitor to Dark Shadow for summoning the Demon Bird, Yaiba reveals that he used the group to perfect his dark power to use the "Three Headed Dragon of Darkness" to bring eternal darkness to Earth with Yaiba ruling over it. However, it rejected him as his darkness wasn't worthy. However, Yaiba had a back-up plan, which was why he allowed Masaumi to live and have him embrace his own darkness. From there, Masumi would use the Precious' power to Yaiba's intent.
However, when Yaiba exposed his goal to Masumi, the light within Masumi grew stronger and both engaged in combat while the others stopped the darkness. In the end, Yaiba was ultimately destroyed by Masumi's Hammer Dynamite, leaving the words "There is darkness within you, Masumi Inou...That is the absolute truth...You'll never escape from the Darkness...The power of darkness can never be...Destroyed!!". These words forced a guilt-ridden Masumi to leave the team.
Kamen Rider × Super Sentai: Super Hero Taisen
However, he revived in Super Hero Taisen as a member of Dai-Zangyack. Later on, they united with Dai-Shocker to fight the army of Kamen Riders and Super Sentai, including his enemies the Boukengers. In the charge, he was seen throwing a punch over GokaiRed, but was caught by GokaiPink. He is then seen fighting KirinRanger, GingaRed, Heart Queen, and GingaPink.