[2] Arii made his professional debut against Yuki Hamada at RISE WORLD SERIES 2019 Semi Final Round on July 21, 2019.
[4] Arii faced the unbeaten Ryoga Terayama in his third and final fight of the year at Stand up vol.1 on December 22, 2019.
[11] Arii participated in the 2021 Cage Kick Championship tournament, held at Shooto 2021 Vol.4 on July 4, 2021.
He was able to beat Ryunosuke Omori and Takuro by unanimous decision, in the quarterfinals and semifinals respectively, but came up short against Ryoga Terayama in the finals.
[16] Arii faced Koyata Yamada at RISE WORLD SERIES / SHOOTBOXING-KINGS on December 25, 2022.
[20] Arii was scheduled to face Musashi Matsushita at RISE EL DORADO 2024 on March 17, 2024.