Shinobu Tsukiyama is a ten-year-old boy from a ninja family in Yamagata Prefecture's mountains, specifically Yonezawa. His mother Chiaki Tsukiyama, father, grandfather, and great-grandfather resided in a small mountain hut before moving to Okinawa near Episode 45.

Raised in rigorous ninjutsu traditions, Shinobu displays a quiet, reserved, and enigmatic demeanor. He showcases extraordinary physical abilities for his age: mastering stealth to approach undetected behind individuals like Akita Oga, leaping safely from extreme heights, sprinting at blistering speeds, evading attacks blindfolded, and demonstrating flawless precision with shuriken.

Though stoic and focused, Shinobu deeply cherishes the forest environment tied to his heritage. Initially a solitary operative, he gradually embraced teamwork through missions with Akita Oga, forging trust and friendships with Akita, Hayato Hayasugi, and Tsuranuki Daimonyama. He eventually rooms with Akita and Tsuranuki. His bond with Akita strengthens through their shared rural roots and wilderness affinity, though Shinobu retains a distinct Tohoku accent.

As pilot of the Shinkalion E3 Tsubasa and later the E3 Tsubasa Iron Wing, Shinobu employs ninja-inspired tactics. The purple-hued unit excels in agility over durability, utilizing holographic illusions for misdirection, flash-step maneuvers for rapid repositioning, smoke screens, and a transforming Fuuma Shuriken that shifts into kunai claws. A cloaking module offsets its visually striking design.

Shinobu evolves from solitude-seeking reserve to valuing camaraderie. Overwhelmed by emotion on his intended last day as a pilot, he chose to stay with his team. He later integrates into Sora’s unit alongside Hayato’s alliance, connecting with fellow pilots despite his shyness.