Bring the Mysterious Mogu Sigil to Lorewalker Cho at the Seat of Knowledge in Vale of Eternal Blossoms.
<The slain mogu clutches a sigil in his hand -- a symbol of the mysterious clan he belongs to.
Perhaps if you could track down his clan, they may know more about the mantid's invasion of Mogu'shan Vaults and how they can be overcome.
Lorewalker Cho is well known as font of lore for Pandaria. He may be able to track down the origins of the mogu's sigil.>