What do you want Harald to do about it exactly? Rebel against them along with his entire nation and get folded like laundry?
People have to remember that even if Harald aligned himself with Rocks (which he wouldn’t do, he’s a King he can’t be selfish anymore) the plan still wouldn’t be complete
Rocks still didn't have the fruit he was supposed to eat, they still hadn’t found the frozen giants, and they didn’t have any of the ancient weapons
It was cooked from the start