The god of Mount Olympus come down from their thrones to accept praise and gifts from the mortals.
The mortals do not offer praise to Hades. This infuriates and insults Hades causing him to react by releasing Cerberus.
Upon release Cerberus attacks the guards killing one of them. He is quite savage and departs the underworld to kill the offending mortals per Hades command.
After his departure from the underworld, Cerberus stalks and locates the offending mortals and kills them.
Cerberus is very proud of the deaths of Zlight and Paul. He returns their souls to the underworld eager for Hades approval and praise. On his way back to the underworld he causes a major earthquake.
Hades confronts the mortals regarding the insulting comments. Zlight and Paul pretend to be ignorant regarding the comments. Hades doesn't accept their denial and sentences them to an eternity of torture.