Guild Wars 2

The skill you need to use with Aurene against the final boss is locked and can not be used. That boss does not take 1 hitpoint of damage either.

Are you talking about the Precocious Aurene instance in A Crack in the Ice?

If so then the new skill only activates at certain times, and is the only way you can do significant damage to the boss (because the idea is you’re training Aurene to fight, so she needs to attack, you’re just telling her when).

You need to wait for the white circle to appear on the ground, then stand in it and use the shout skill. At other times you should focus on avoiding their attacks so they don’t heal.

There’s a more detailed walkthrough on the Wiki, the wording isn’t great but it might help: https://wiki.guildwars2.com/wiki/Precocious_Aurene