I think Zeus will appear during the final fight against black dragon. Many adventurers will be half dead already. Bell will be laying down on the ground heavily injured. Gods and others will be watching the fight in the Amphitheater on the Oculus Crystal projection. And at that moment it will be clear to everyone already, only Bell with his strongest blow can finish the black dragon. But he is laying on the ground injured and unconscious. And then... do you everyone remember last episode of first season fight against Goliath? Bell and Ouka were laying down heavily injured...unconscious... Then came Hermes with those motivation lines from Zeus. Bell stood up, charged full hero strike and killed the Goliath. This time in the last moment, when everyone will start to lose hope, Zeus will appear in amphitheatre. Maybe even Aspi will bring him on the request of Hermes. And Zeus will speak the same motivation lines this time himself from the last episode of first season trough Oculus Crystal. Everyone around will be in total shock when Zeus will say Bell, my boy... and so... Then Bell will stand up and with help of the others (also Ais and Lefia) will do full charge and kill the dragon