I'm doing the Alduin's Bane (I think) quest where I just used the Elder Scroll to learn Dragonrend. Now, I'm back in normal time and I do 0 damage to Alduin. I fought him for about 10 minutes or so and his health bar never moved. I read that it may be a glitch and that I'd have to clear my XBox cache and wait for him to stop talking. So, I did this and the same thing happened.

Any pointers?

Use Dragonrend. It's the only way to make Alduin mortal.

Welcome to the forums by the way.

Thank you for the welcome

I used Dragonrend. I had him grounded. My Dark Brotherhood Initiate was wailing on him, the draemora dude I summoned was wailing on him, I was wailing on him, that other dragon was wailing on him. I had it to where I was behind Alduin and would Dragonrend both him and that other dragon (I don't know how to spell or pronounce his name) and so they both stayed grounded and focused on each other. This was to no avail