Oriath the fool, god of death and undeath, the thief of domains and the great pretender, has been trying to subvert the system used to summon hero’s for centuries. Blocked from having much influence to mortals by the other gods, he spends decade after decade in his personal demiplane tinkering with powers that are best left alone.
He has actually had some amount of success! He can at great cost use the system for summoning hero's to take souls from other worlds and send them to other worlds, but not his own. The system is far too locked down and watchful to allow meddling on that level in his own world.
Oriath has some vague plans about what to do when he has finally subverted the hero summoning system. He wants to summon his own army of hero’s so he can actually change things, maybe use them to kill the other gods for all of their evils. If its even possible then he has a more ambitious plan to make sure that every single dead soul across the many worlds is summoned somewhere else when they die, thereby eliminating true death.
This time Oriath thinks he has it, a way to fully break the restrictions on this system. The ritual takes years. Titanic amounts of mana, both divine mana and mundane mana, are being channeled. Eldritch glowing glyphs circle the great pretender and burn their way through the rules of reality.
The system is not so easily subverted, the glyphs shatter into sparks, the mana goes out of control, and the system swats Oriaths entire demiplane out of existence.