SGRKing

Alduin (TES) Dovahkiin can destroy Alduins physical form easily once he's attained Dragonrend. After asking Arngeir if he wants to destroy Alduin since the Blades want to, he responds with,

"What I want is irrelevant. This Shout was used once before, was it not? And here we are again. Have you considered that Alduin was not meant to be defeated? Those who overthrew him in ancient times only postponed the day of reckoning, they did not stop it. If the world is meant to end, so be it. Let it end and be reborn."

This implies that Alduins true self is indestructible since he's a mandatory counterpart to the functioning of the kalpas. A piece of the most powerful deity, Akatosh.

Thor Welp, I was going to use the fact that Thor can ONLY travel faster than the flash while spinning Mjolnir in order to travel billions of times faster than light through space, but that's not true. He has demonstrated extremely fast combat reaction speed against Silver Surfer. This means that he could definitely keep up with Barry... and yes, lightning effects Speedsters like it would effect any other human being. If your average Thor were to go up against Wally West, maybe this battle would pan out differently.

Iron Man I've tried and I've tried and I just can't think of any way that batman can win. Maybe that's cause I just got done watching the 1966 Batman movie. After extensive research on both sides, without a doubt, iron man would win.