"I did it because I couldn't do it myself, so I needed you."
- ―Saku explaining why he gave Jin the Glass Memorial binoculars.
An alien from an unnamed race, Saku and his younger brother Nozomu traveled to Earth and journeyed through various places. One day, they stopped at the Saginomiya household area to seek a temporary refuge. At the same time, he became aware that his younger brother had fallen in love with Mahiru Saginomiya, a young woman of the Saginomiya family and he also witnessed Nozomu turned into Jyuujin and unintentionally killed her before he disappeared and slumbered underneath the city's tunnels for a hundred years. Saku would later lived as a normal human named Toshiyuki Ogata (尾形俊行 Ogata Toshiyuki) and would tried to seek help when his brother finally arise from his slumber.
100 years later, his brother awakened and his hope finally came when witnessing Jin and several DEUS agents. He left Jin his memorial glass binocular and went to agent S's office, revealing several files about the beastman incident that occurred a hundred years ago. While Jin and two other of his friends gathered at the Saginomiya household, Saku revealed the history behind Jyuujin and Nozomu while keeping his presence from a century ago secret. As he took the binoculars from Jin, the trio DEUS agents decided to wait at the mansion at night to hunt the beast.
Jin, however, felt something mysterious about Ogata and went to his office, only to found out he was Nozomu's older brother. As they chased the fiend through the underground tunnel, Jin transformed into Ultraseven and launched his Eye Slugger through his brother who fell and died in Saku's arms while dissipating into light particles. Jin realised it was he who left the binoculars the other day, for him to seek Jin's help. Saku disappeared with the binoculars.
- Saku/Toshiyuki Ogata was portrayed by Hassei Takano, whom also previously portrayed as Hiroya Fujimiya/Ultraman Agul in Ultraman Gaia 8 years prior.
- Saku's name is a Japanese word for new moon, the first phase of the Moon, when it lies closest to the Sun in the sky as seen from the Earth.
- Height: Unknown
- Weight: Unknown
- Origin: A distant planet from Earth
- Weakness: Like his younger brother, Nozomu/Jyuujin, Saku cannot make contact with water, otherwise he will became a rampant beast.
- Powers and Weapons
- Agility: Saku could perform numerous acts of inhuman agility, such as jumping extremely high or running quickly.
- Outspace Adaption: In a flashback both brothers are seen on the moon without any protection.