|Family and Relations|| Juzo Kabuto (Grandfather),
Koji Kabuto (Older Brother)
|Voice Actor||Sayaka Aida|
|First Appearance||A Fierce Fight! Double Mazingers|
Shiro's appearance in Mazinkaiser is based on how he appeared in the original manga, short black hair and black eyes, a yellow short sleeved shirt, dark blue shorts, and white sneakers.
Shiro is a mischievious young boy who always looks out for his older brother, Koji. He holds him and his grandfather's robots in high regard, never doubting Koji or the Mazinger robots. At times he likes to poke fun at Koji and Boss. Shiro also shows a lecherous side when around girls like Sayaka or Lori & Loru.
Shiro was in the Photon Lab as he witnessed the Mazinger Z become overrun by Mechanical Beasts and Koji ejected into the distance. Believing his brother to still be alive, Shiro went with Sayaka on her motorcyle while taking delight in the fact he could hold onto her. He later noticed Mechanical Beasts approach the Photon Lab with a modified Mazinger Z under the control of Baron Ashura. Fortunately, the Mazinkaiser appeared and defeated the robot before attacking the Photon Lab. Shiro then noticed Koji in the cockpit of the robot as Sayaka called out his name. As the Kaiser stopped and Koji left unconscious, Shiro would visit Koji with Sayaka as he recovered.
By the time Koji woke up, he and Boss found Sayaka hugging him while taking the opportunity to make fun of them. As the Mazinkaiser is analyzed Shiro asks his brother if he saw their grandfather. Koji replied that he did and was unsure if Dr. Kabuto is still alive and active. Soon an alarm went off with Mechanical Beasts attacking Japan.
For the rest of the series, Shiro had a very small role; mostly acting as a supporter for Koji and the rest of the team. On their beach day, Sayaka was kidnapped; Mazinkaiser and Boss Borot went to rescue her while Shiro remained behind with Lori & Loru. The twins offered Shiro to put tanning oil on them and vice versa, something Shiro took a perverse delight in. After Sayaka was rescued, Shiro was deeply tanned and being felt by the twins, which made Koji jealous.
During Prof. Yumi's birthday, Shiro helped with the directions while noticing how strange the professor was acting. He then caught on that it was an imposter based on what Loru said. As Baron Ashura removed his/her disguise Shiro watched as Mazinkaiser fought the Toros D7 before it was destroyed by a Ghost Mechanical Beast. Shiro was in the crowd as more Ghost Mechanical Beasts attacked the Photon Lab the next night. Shiro gave his full support to Koji and the Kaiser, and was worried sick when they were thrown into an active Mt. Fuji. Thankfully, they survived thanks to the Great Mazinger and the Kaiser Scrander. After the destruction of Hell Castle, Shiro heard his brother's voice as he returned to the lab.