Nozomu Amachi
He is the young son of the professor, he is in the fourth grade. When Alata first spots him, he sees him being teased and tells Nozomu to believe in himself and he can make friends. He gets Alata's transformation card by mistake. Hyde prepares to erase Nozomu's memory of them but Alata stops him, saying he is his friend. Nozomu returns him with the card when he realizes he needs it.
Professor Shuichiro Amachi
Professor Shuichirou Amachi is Nozomi's father and an amateur astronomer who runs the Amachi Institute. His wife Yuko works away from home and rarely comes home. He hires the Goseigers as part-time workers, unaware of their actions. Regardless, Amachi aids them on certain occasions and eventually learns the truth about the Gosei Angels from Master Head after agreeing to be his medium to talk through due to being of pure heart.
Datas
Datas is a robot that is sent by Master Head to Earth, prior to Heaven's Tower being destroyed as both an emergency system and means for communication between the Gosei World and Earth. Tending to end his sentences with "desu", and usually sleeping when not needed, Datas also can pinpoint the likely location of villain activity. His form resembles the Super Sentai Battle: Dice-O arcade machine. Datas turns into a giant robot called Datas Hyper by combining with the Hyper Change Headder when needed.

Master Head
Master Head is the leader of the Gosei World and he is the Goseigers' only contact to their homeworld. He provides them with info on how to fight Warstar and the Yuumajuu. In the end, Master Head sacrifices himself to provide the Goseigers with Gosei Ultimate. However, Master Head's spirit endured, ending up in another dimension. Master Head temporarily possesses Professor Amachi to give the Goseigers assistance, giving them insight about the Yuumajuu's sealing and Brajira. He played a role in giving Gosei Knight the power to help in the Goseigers' final battle with the Matrintis Empire.
Magis
Magis was a member of the Seaick Tribe and the former partner of Hyde. Before the first series, he briefly transformed into Gosei Green in order to save Hyde but was was killed by Kurasunigo of 5000°C. Magis only appears in flashbacks.
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