Dr. Hoshi (1-2)
The principal of Academia, made the Gran Tortoise and gave the Liveman mecha the ability to combine before dying. He died helping a pregnant woman trapped in the rubble of Academia Island escape. Played by Ban Naoya (Kikaider, Inazuman, and Captor).

A female robot built by Doctor Hoshi in charge of Gran Tortoise, assists the team. She frequently supports Liveman on foot, car, bike, and the Machine Buffalo (especially before Black Bison and Green Rhino join). Since Ashura appeared, Colon wanted to be more help to the Livemen and met Tanaka, a malfunctioning Dummyman who fell in love with her before he sacrificed himself to save her from the monster Dokugas Zuno. She later fell in love with Yusuke (who treated her coldly at the time until she saved him by taking a sword cut meant for him). She is able to swim, or otherwise move underwater, perhaps as part of being in charge of the Gran Tortoise. She has a habit of saying "Colon".

Takuji Yano
An Academia student studying on the powering suits for space travel with Yusuke, Jou, Megumi, and Mari. The older brother of Tetsuya and Takeshi. His prototype power suit featured a swallow. Yusuke was his best friend. He was killed protecting his friends from Kenji's blasts. He promised his youngest brother Takeshi to build a dream car with him, his death resulting in the death of Takeshi's dream until he approached Yusuke who agreed to help him build it, creating the Live Cougar. In the GaoRanger VS. Super Sentai Yusuke is found visiting his grave.

Mari Aikawa
An Academia student studying on the powering suits for space travel with Yusuke, Jou, Megumi, and Takuji. The older sister of Jun-ichi. Her suit featured a dog. She was also working on the plans for the Bison Liner and the Sai Fire before her death. In the GaoRanger VS. Super Sentai Yusuke is found visiting her grave.

Doctor Dorothee
Tetsuya's and Junichi's benefactor, the leader of the Academia group that built the Bison Liner and the Sai Fire. She later arrives to help the Livemen by providing a new power core for the Bison Liner.

Takeshi Yano
The younger brother of Takuji and Tetsuya, he met Yusuke and the others before Takuji was killed by Volt. He helps Yusuke complete the Live Cougar vehicle, which Yusuke started to build with Takuji. He is considerably younger than his two brothers and very little mention is made about his relation with Tetsuya.

Toshiko Omura
Go's mother. When Go was young, Toshiko pressured her son into succeeding academically at the expense of giving him a normal childhood. When Go returns to her home for refuge while hiding away from Volt, she becomes terrified when she witnesses her son's transformation into the monster Dr. Obler. Yusuke makes her see the error of her ways and she manages to revert Go back to his human form by reminding him of the motherly love she gave to him as a child.

Yoichiro Misaki
Megumi's father. A master of a form of archery known as the Higo Cross style. He goes to Tokyo to visit his daughter with the intention of paring her with a potential marriage partner. Although his archery skills has deteriorated as a result of his age, he is able to see through Volt's disguises when a group of Dummymen posed as hostages. He becomes proud of his daughter when he sees her use the Dolphin Arrow.

Mai Funachi
A long-time friend of Yusuke who works as a day-care worker in a kindergarten, who also knew Kenji before he became Doctor Kemp. When she was a high school student, Kenji gave her a bouquet of roses he specially bred known as "Kenji Roses", which helped her mother recover from an illness due to the positive energy it radiated. Later, when Kenji suffered an accident from a lab experiment, she donated her blood to save his life, as she carries the same rare blood type (ÃY ZO Negative). She still holds Kenji in high esteem, until she finds out that he has become Doctor Kemp.