The Bisil are a race of insectoid aliens affiliated with the Warp Monarch. They are the antagonists of episodes 26 and 27 of Chouseishin Gransazer.
The Bisil came to Earth to test out their dimensional transport system, and use it to teleport humanity off of planet Earth. They disguised one of their members as a deceased schoolgirl named Asami Yoshioka to befriend the Gransazers and keep tabs on them.
They initially tested their system on a few individual humans but the Gransazers soon caught on. The Bisil prepared to use their system to teleport all of humanity off Earth, but the Gransazers learned the location of the system from Asami after she was assassinated by the other Bisil for trying to defect.
Sazers Tarious, Mithras and Visuel went to go destroy the device, fighting off a squad of Bisil soldiers. Eventually, Tarious destroyed both the Dimensional Transport System and the Bisil leader with a shot from his Falcon Bow.
The Gransazers were later ambushed by the Bisils' mothership. The three Flame Tribe members summoned Garuda and used it to destroy the mothership.