Resulting in the protagonist being the super badass but mysterious mentor character who says cryptic shit to the hero and then vanishes without explaining anything
So you'd have a scene where they had that spell up and were trying to explain things to the chosen one but before they can get into the meat of things the mage is like "Two minutes"
So you've got the party of young, stalwart heroes who are fighting dragons and freeing down and then you've got the party of older, tired, more morally gray heroes who have already failed to save the world and now are working in the shadows so that someone else can still get a chance
I feel like you'd want something like "Your party is holding off the mooks and/or sneaking around doing the set up for said NPC to be CAPABLE of saving the day instead of getting completely murdered."
[LOCATION OF THE NEXT PLOT MACGUFFIN]"I support this.