He is the first hunter that Samus Aran will stumble upon, and the first one that she must defeat. He is a former Space Pirate who was nearly killed by Samus prior to the events in the game. The Space Pirates saved Weavel by giving him an operation similar to Ridley's - Implant his brain and spinal cord into a robot's body.
"A cyborg Space Pirate and member of a special-forces unit. Weavel was once left for dead in a fight with Samus. Like other hunters, he also seeks the ultimate power. His weapon of choice is the rapid-fire, heavy duty Battlehammer. Weavel can transform into the Halfturret where his upper and lower body split and can attack separately."