Adin knew that he was the one who must fill the medallions in the belt.
Sparking rod is in need of more information! Sparking rod is lacking an example with Pi-Ban as well as the scene in the Shadow Arena where Lief, Barda, and Jasmine get knocked out with sparking rods (and Emlis is the only one to escape).
A Vraal chased the companions to the door of the Factory. The companions escaped inside but the Vraal kept bashing against the door alerting Grey Guards in the process. They came to investigate and when they realised that a Vraal was on their doorstep they considered using the new sparking rods to deal with it.
The effectiveness of stun is based on the size of the victim (ex. two strikes against Barda; one against Lief and Jasmine). A chain effect occurs if all the energy per strike is not used transferring the remaining energy to next closest victims (ex. Jasmine with Kree). If there are no victims nearby, the shock can be lethal since all the energy is forced onto one.