The Hammerhead is an aquatic Zoid, but is also capable of flight. It can be equipped with CP- 14 Viking Lance to improve its melee capabilities. However this upgrade removes most of it's ranged weaponry.
Having struggled against the ambush tactics of the Zenebas Empire's sea and air Zoid Sinker during the old war, the Republic Army transport forces developed the Hammer Head as an opposition to the Sinker. It is a high-mobility sea and air Zoid which uses variable wings as its main wings, and is equipped with ion engines that operate efficiently in both the sea and the sky.
[ZAC 2100] A second all-out engagement began between the Guylos Empire Army and the Helic Republic Army, which were confronting each other on the continent of North Europa. The Empire Army began a general attack before the Republic Army's main Zoid force, which had landed on Europa, could ready their combat preparations. The Armoured Division, made up primarily of the PK Force, approached the Republic encampment from the front, and a mixed marine force of Brachios, Hel Digunners and Sinkers approached from the sea behind it. But the Empire Army had absolute confidence in their naval forces, and made a great miscalculation. The Republic Army had deployed their cutting-edge sea and air Zoid, the Hammer Head, in the ocean. The Hammer Head exterminated the Sinkers in the blink of an eye, then calmly sank the Brachios and Hel Digunners from the air. Meanwhile, on land, a major counterattack by the Republic Army's main Zoid force was about to begin.
One of the more prominent appearances of the Hammerhead is in Guardian Force. A similar Zoid known as the Hammer Kaiser was used as a transport. The Hammer Kaiser seen is many times larger than the Hammerhead, as Hiltz used it to carry the Death Stinger in its cargo bay. This version of the Zoid also achieves altitudes that could only be matched by Storm Sworders with massive boosters equipped. From there, it was used as a turret to bombard the planet with Charged Particle Cannon fire. This Zoid was defeated and crashed into the land.
The Hammerhead is also piloted briefly by Reese in episode 12 of Guardian Force, where she fights Van in the ocean. Here the Blade Liger is quickly outmatched, due to its inability to use either its shield or laser guns while underwater.
A Hammerhead is briefly piloted by Thomas Schubaltz and seemed to be equipped with BEEK.
Many other Hammerheads appeared throughout the series. However, they mainly served as transport Zoids for the Helic Republic, including the President's personal transporter, which are usually seen with a Storm Sworder escort.
The Fuma Team under instruction of Dr. Laon kidnap Harry Champ and tie him to a Hammerhead. They used this as a bargaining chip to attempt to defeat the Blitz Team. It seemed to work at first, taking out both the Liger Zero and Shadow Fox, but the plan ultimately fails when Leena shoots down the Zoid, seeking revenge against Harry for setting her up on a date without her approval, much to Laon's shock and a distraught Fuma.
The Hammer Head appears in Zoids: Legacy, as well as the Hammer Head VL which is a Hammer Head with the Viking Lance Customize Part attached.
The Hammerhead was featured in the Republic Booster Pack of the Original Battle Game and in the Volume 2 of the Trading Collection Card set of Zoids Trading Cards.
The Hammerhead was released as part of the Zoids (1999) line.