This sigil was given to me by a messenger from our rogue trainer, Frahun. It seems Frahun would have words with you when you have a moment. Read it and bring it to him afterwards.
Until then, know that our kind are needed more than ever in this tenuous time. Peace with the other races can fail at any moment, and there is much talk about members of the Horde looking to sow even greater seeds of distrust. Remember that.
As you gain in power and feel more prepared, come back to me here and I will see about getting you some training. It's important that you know how to handle your weapon of choice, among other things.