Hey guys,

I'm on the quest and when i hit him he take 0 damage, help?

Thanks guys, Bye

Use dragonrend, he can only be hurt while it's in effect

A very common bug, it happens when you use dragon rend on him during the sequence when hes still talking to you, you HAVE to wait for him to stop speaking before using dragonrend. My advice is to only use dragonrend when parthumnmax tells you to, once he has, spam it on alduin as much as you can.

Only way to fix it is to load an earlier save, and make sure you (if you wanna save time for when you die during the fight) is to save the game after right after hes stopped speaking.

That is very good advice. So, yes. Reload the fight and only use Dragonrend once he stops talking. Hopefully that will fix your problem.

Turtles cannot fly, I cannot fly, therefore I am a turtle.

Sorry I just couldn't help but antagonize your deductive logic.

It won't work