Arthur Grant is one of the main characters of Ultraman: Towards the Future. He is the captain of UMA.
History
Ultraman: Towards the Future
Grant is considered a hard-working and upright commander who can calmly analyze intelligence in an emergency. Although he never told the team members what he had learned, he often acquiesced in allowing the team members to play to their strengths.
He didn't trust Ultraman Great at first, thinking that it was a biochemical robot sent by aliens, but after seeing Great's desperate battles many times, his attitude towards Great gradually became friendly. After the events of Super Gudis, he officially recognized Great as a human ally. The Showdown
In the series finale, he and the team watch Great leave Earth. Nemesis
Other Media
Ultraman Great Manga

In the manga adaptation, Arthur Grant appears as a main character, with his personality, experiences, and actions remaining consistent with those depicted in the original TV series.Ultraman Great (manga)