Grendel's forked staff is his primary weapon. Hunter Rose originally chose the design in order to further the demonic imagery associated with his alias. In his usual style, Rose added enhancements to the staff that would make it even more deadly.  This staff would get passed down to Christine Spar years after Rose's death.

Features

First, the forked blade is undetectable by metal detectors or any other security measures, yet its steel blade is razor sharp. The blade itself is retractable, and can be completely hidden in the hilt. In this way he can keep the staff with him at all times as a walking stick, and can still use it as a weapon whenever he chooses. Circuitry within the staff allows the blade to be electrified with the touch of a button, but the charge doesn't last very long.

There is also a radio transmitter located in the staff so he can use it for communication.

Eppy Thatcher's staff

A similar staff was crafted hundreds of years in the future by crazy genius Eppy Thatcher to be used as a part of his own Grendel persona.  Unlike Rose's staff, Thatcher's blade was not retractable (as Thatcher did not use the staff when he was not Grendel).  Thatcher's staff used an extremely hard blade, and had technology incorporated into it that allowed him to override other technology such as the church's automated collection plates.