The Wizard Great World has dominated this Star Domain for countless ages and is, indeed, a true overlord!
A vast world occupies the void, its influence radiating to surrounding realms, causing all beings in various worlds to tremble in fear whenever they hear the name of a wizard.
Especially those worlds already occupied by wizards, their reverence for wizards genuinely comes from the heart, not daring to incite any offense.
Otherwise, being slain is considered an exceptionally good outcome, as being sent to the experimental table, becoming an experiment and enduring endless torture, would make them regret coming to this world.
Some unfortunate souls are not even granted peace in death, with bodies turned into specimens, even souls possibly imprisoned within, waiting for a wizard's whims or becoming study tools for other wizard apprentices!
Not that there are no strong resistors, nor do all worlds willing to succumb to the brutal rule of the wizards.
