Hel is a minor antagonist appearing only in And Another Thing... and The Hexagonal Phase. She one of the norse gods residing on Asgard and the ruler of Helheim, the underworld. She was put in charge by Odin of firing missiles should Asgard face an invasion. She was given the order to fire the pressure cannons only if the code, Compliments to the under-brazier, and the failsafe bong-o-code had been given to her.
When Zaphod Beeblebrox had unintentionally transmitted the code to her, she panicked, thinking Asgard was under attack, until her familiar, Modgud, managed to calm her down by reminding her she still needed the failsafe bong-o-code. When Zaphod then unintentionally transmitted the failsafe bong-o-code, Hel fired the pressure cannons, thinking this was her ticked out of Helheim. The cannons ended up hitting Heimdall's dragons who had been about to kill Zaphod, enabling Zaphod to be able to give Heimdall his nickname, Bentstick, allowing Zaphod to escape and be the first mortal to successfully cross the Rainbow Bridge into Asgard.