Данкугар

Emperor Muge Zarbados and his Empire of Death decide that their next conquest will be the faraway planet of Earth. Muge becomes even more fearsome because of Shapiro Keats, a power-hungry Earthling-turned-traitor. It's up to Shinobu, Sara (Shapiro's old girlfriend), Masato, and Ryo of the Jyusenkitai/Cyber Beast Force to pilot the four Jyusenki/Beast Mecha (Eagle Fighter, Land Cougar, Land Liger, and Big Moth [a mammoth mecha]), which can combine into the giant mech Dancougar. (Source: ANN)