>>58818818The real answer, remnants of a corrupt league plot that they couldn't remedy in time.
The cope answer depends on which continuity you're looking at (good intentions fueled by trauma in the anime, the crisis being much sooner than 1000 years in the manga, etc.) but for the game itself, it's more than likely that Rose, who has at least decent intentions trapped behind a massive ego, wanted to immortalize his place in history as the greatest chairman of the Galar Pokemon League of all time, the brilliant mind who personally saw Leon's potential from the very start and built up to his uncontested position all to make sure Galar, if not the world at large, could know peace from the someday threat of Eternatus returning, and through Eternatus' defeat, Galar would know everlasting prosperity thanks to its endless amounts of energy being used to power the region.
