Throughout the twelve universes, there is a single Hakaishin per universe, which they overlook alongside their universe’s Kaiōshin. Since both Hakaishin and Kaiōshin share their life-force with each-other, a Hakaishin will die if their universe’s Kaiōshin perishes, resulting in their Angel attendant ceasing to function until the deceased Hakaishin is replaced. For this reason, the connection between the pair isn’t public knowledge. For a Hakaishin to die, all currently appointed Kaiōshin must die, evidenced by the fact Beerus did not die even though four of the five Kaiōshin were killed by Boo. However, their lives are not linked to previous Kaiōshin because the Beerus in Trunks’s timeline died when the Shin of his timeline died even though Old Kaiōshin was still alive and sealed within the Z Sword. Every millennia, the acting Hakaishin will coordinate a meeting with the current Kaiōshin in their realm. What occurs at these meetings, however, is unknown.
Many, including the Kaiōshin have misconceptions about the Hakaishin’s duties. Old Kaiōshin, despite his vast age and knowledge, believe Beerus might even destroy the Seventh Universe, which might have happened at least once in the past due to Beerus’ temper, if not for his assistant Whis keeping him in line.
Matching with their thematic role a Hakaishin holds the power of Destruction, a special ability that allows them to potentially destroy any target they desire.
It is hinted Hakaishin are also meant to induce a form of Natural Selection to develop a universe’s power ranking by destroying planets with species that are developing at a slower rate.