Right before the Dragon melts the Iron throne, out from a portal pops out Iron Man.
A mysterious entity revived him after End Game and landed him smack at the end of Game of Thrones.
Iron man puts up a force field to block the fire and pins down the dragon using an electromagnetic net.
Jon Snow looks at Iron Man..."Who are you?"
Iron Man: Isn't it obvious or have you never heard of me...Iron Man?...Tony Stark?....
Jon Snow: Stark?!
*now maybe this doesn't lead to the ending in the title, but how would this play out with Iron man having his Endgame suit, and carrying the last name of a major family?
Could he be the hero Westeros needs or will they turn on him as his snarky attitude and remarks may get him into trouble?