Skullus

The Skullus is one of the primary weapons used in Wyvern Island. It has two forms: the Fishing Rod Form and the Sword Form.

Fishing Rod Form
When the Skullus in its Fishing Rod Form, it takes shape of a normal fishing rod except for a couple of notable differences. One of the differences is that there's no hook at the end of the string—since the string changes shape, material, and size when you've used it on something. The reel also is slightly different; it is now only a simple lever (Or the Grappling Control Lever), and it's not even connected to the string. Once pulled, pistons and different mechanisms inside the main body of the fishing rod works to either reel the user towards the end of the string or reel in the captured object towards the user—depending on what direction the lever was pulled. The control gem (Or Merge Control Button) is placed on the butt of the fishing rod, and pushing this changes the form of the fishing rod.

Sword Form
When the Skullus in its Sword Form, it takes shape of a normal 3-5 feet sword. It has a normal steel blade that can cut through objects. The control gem (Or Merge Control Button) is placed in the middle of the front side of the hilt, and pushing this changes the form of the fishing rod.

Successor
The Bullus is invented to serve as the successor of the Skullus. It is an improved weapon and, according to Animos, more efficient and stronger than the Skullus.