If you still want to proceed with downloading the Grimm web series from Filmyzilla, here's a step-by-step guide:

Downloading the web series Grimm from pirate sites like Filmyzilla is due to significant security risks and legal issues. Why You Should Avoid These Sites

is frequently available for streaming or purchase on Amazon Prime Video in many regions. Apple TV / iTunes:

: You can buy or rent high-definition episodes or full season sets here.