Aspera Giant-Friend says the giants are about to go to war against the Stormfists that hold Cradlecrush because their Mammoths were stolen. As long as I oppose the Stormfists, these giants will consider me to be an ally.
Use the Horn
Aspera Giant-Friend gave me a horn. I need to use the horn at a nearby cave to summan a giant ally.
Collect Stormfist Scout Orders: 0/4
Now that I have a giant ally. I should be able to use its strenght to knock the Stormfists scouts from the trees. Then I can kill the scouts and collect any orders they may have in their possession.
— game journal