Very few fans will argue with the fact that 2007 was a great Bionicle year. That doesn’t mean it’s without some shortcomings, one in particular being Hewkii Mahri’s set design with his missing hand being the biggest eyesore.
This has been a large criticism since he was first released but I’d like to propose a theory that might explain It’s not that he doesn’t have a hand, it’s that we can’t see his hand. I’m thinking it’s something similar to something like when Iron Man has an arm cannon.
He doesn’t have to cut off his hand to use it, his hand is just covered by it. In the same way, Hewkii might just have some sort of sleeve-type thing over his entire arm that the Cordak blaster is attached to. This might also explain why that arm is a different shape and color.