I wish i had taken note of what the 'season' was when I killed this, but I didn't. I killed it the day before yesterday (Feb. 19th), so most likely it was still the month of Grayeven, since today marks the 25th day of Grayeven.
It spawned near the North gnoll cave entrance. Be VERY CAREFUL of where you fight it, !!IT BREAKS ENCOUNTER FOR NEARBY GNOLLS!!!. We killed it with 2 full groups, our tank was lvl 27 and we had no problem. No loot to report though..since it broke encounter.