This is Buraiken, Zaerus's Guyver Control Metal. This is a pic of Buraiken by himself. As in, this isn't Zaerus wearing the Guyver suit. He doesn't allow the Guvyer to wrap around his body in a suit in fear it'll take over him. Instead, Zaerus is host to the Guyver Unit and it uses tentacles as a means to protect Zaerus and interact with the world. This is how Buraiken would look on a normal humanoid host, or if he were ever to be a standalone entity.