Okisaba/Oxaba feature the Tokyo Marui HK416D Akki Custom NGRS. Akki is an Japanese active airsoft player and has got various loadouts and gear that he features on his Twitter account. The base gun is probably the DEVGRU Custom variant inspired by US Navy SEAL's customized rifles, upgrades the HK platform with steel parts, enhanced stability, and realistic features like simulated recoil and magazine-empty stop.