Is this a spoiler?
Don't know. Don't read. Lol
But you can get the ogres to fight for you more than once, takes money and or a good roll.
Just keep in mind if the Ogre leader dies you won't be able to use the horn again. Not sure if intended or bug.
Interesting I never even realized the horn could be used multiple times, because I kept saving it up for a good moment, which never came.