Bunjiro "Bunji" Tsukahara, aka Karate-1, is Jack's and Helen's Japanese foster son. He was placed under their guardianship after his own father disappeared 10 years earlier somewhere in the East. Bunji is an avid karate enthusiast. As Karate-1, his already-formidable martial arts prowess is enhanced by his bionics. He is the most agile among the Six, and his super-sharp reflexes are surpassed only by those of Rock-1