See Party Missions for general overview of party missions. This party mission is somewhat similar to Panfilo's Protector of the Cows quest mission, which uses Rion Praire map. The objective is to protect the cows/bulls from wolves, destroy the 4 colonies, and kill Gray Wolf Boss.
Wolves (L90 Life) will come towards the cows, then return to the boss after killing a cow. If a cow is killed, there will be a zone notice, saying: The wolves killed the cow and they are returning to Gray Wolf Boss with the meat. There are [number] cows remaining. Do not let all the cows die.
If you kill the wolf before it reaches the boss, there will be a zone notice, saying: You have stopped the wolf from offering the meat to Gray Wolf Boss. Otherwise, the zone notice will say: The wolves successfully offered the meat to Gray Wolf Boss.
Send 1-2 shooters to destroy the far colonies at top left and bottom right. Kill any wolf on the way. Everybody else go towards the boss. On the way there, kill all wolves and destroy the 2 colonies near the boss before attacking it. If you take too long, the colonies may respawn, so keep a lookout on them.
Gray Wolf Boss (L110 Life) has lots of hit points, but poor Mind RES, so debuff lands on it often. Capitalize on this fact. Elementalists can inflict [Shock] status on it with +6 or +7 Bracelets of Ziz. Ranged and melee characters can try to inflict [Fear] or [Stun] status with the appropriate weapons.
After a while, there will be a zone notice, saying: Gray Wolf Boss has become very weak due to extreme hunger. When this happens, it will weaken until its stats eventually become reduced to: ATK Rating 39, ATK 21,918, DEF Rating 55, DEF 325, Fire/Ice/Lightning RES -4, and Mental RES -5.
If the wolves have offered meat to the boss (see above), the zone notice will say: Gray Wolf Boss has forgotten about his hunger after eating the meat served for him. Remaining meat: [number] pieces. This essentially means the boss has regained its original stats.
See also クエスト/狂気の牧場 and Fury Farm - Fight Brasil.