Cadan is an amphibious Zoanoid developed at Cronos Japan. Its specialized skin structure reduces friction, allowing it to swim at a speed of 62 knots (about 70 miles an hour). Suckers on the hands and feet allow Cadan to easily scale the hulls of great battleships and aircraft carriers. Once on board, it can not only employ great strength, but also the ability to spew an intense water jet from the mouth, powerful enough to punch a hole right through a human being.

Cadan first saw field combat against the Guyver some time after the D-59 Incident, but barely got the chance to fight as the Zoanoid platoon was quickly vaporised by the Guyver's Mega-Smasher. Other Cadan units would appear during the Takeshiro Incident, but again were swiftly eliminated by Guyver-III. Success against the Guyvers wasn't expected by then since production class Zoanoids had repeatedly failed many times before then.

Against human opponents, however, Cadan proved to be most effective. During X-Day, Cadan units were deployed against the US Navy to great effect.