Are you familiar with Shattrath City, <class>? Above it to the northwest is a place called the Barrier Hills, which you can only get to upon a flying mount.
One of Gruul's sons, Slaag, exiled himself and took control of the Gordunni ogres that reside there. Even at such a distance, we cannot afford to leave him in peace, lest he return when the rest of his brothers have been slain.
<name>, you must travel there, and bring back his standard as proof that he has been dealt with.