Gunber can combine with his pet dog Zero One to become Gunber 01, then combine with his brother Zetter 99 and Father's remaining support machines to form Zetter Gunber.

Gunber transforms into a Type 9C Volkswagen New Beetle patrol car. He's son of Father and Zetter's youngest brother. He's oftenly naughty and loves to play baseball.

During a small baseball game with the protagonist, Gunber's homerun accidentally broke the Orb of Protection that kept the ancient Demon Jerkin trapped within.

The Queen of Astaria sends our protagonist and Gunber on a mission together to seal the Demon Jerkin once again.