Using Incantation of Haqin at the grave marker "Haqin of the Hundred Spears" will summon this mob.
Haqin is one of three Undead summonable mobs on the Isle of Thunder who drop a Fortuitous Coffer containing Elder Charm of Good Fortune. These mobs are quite easy to solo, but you do have to avoid their attacks. Also note that while these mobs' health values will increase as more players attack, they do NOT have the loot sharing system enabled. Killing them is also part of the achievement series These Mogu Have Gotta Go-gu.
On Haqin specifically, you must run away when he does Whirlwind and run from the targetted area when he uses Spear Barrage.