Walpurga, the Eternal Curse

{1}{w}{g}, pay 2 life: You may cast target curse from your graveyard. (You still pay its cost)
Whenever an opponent loses the game with curses attached to him that you own, each other opponent secretly chooses a number. Reveal those numbers. Each opponent with the highest number loses that much life, and you gain that much life. Attach those curses to the opponent with the lowest number. If multiple opponents are tied for lowest, repeat this process