Great Buffalo is one of the initial Notorious Monsters added in Final Fantasy XIV.
The Great Buffalo will always spawn during the day in La Noscea and despawn at around 18:00 if not killed, regardless of other factors. His general spawning area is north of Camp Bald Knoll, sometimes near Mistbeard Cove's entrance.
The Great Buffalo is one of the two open world Notorious Monsters without any weaker minion helping him during the fight, but makes up for it by dealing massive damage with his moves. His regular attack will easily hit players for upwards of 600 damage, while Pulverizing Pound will probably one-hit-kill ranged fighters that happen to be hit by it. Seismic Rift is his strongest move, dealing 1k+ damage against everyone around him, while the weaker OnRush can still be a nuisance as it Knockbacks players hit by it. Sonorous Blast is a AoE enmity reset.
The most common strategy is to use one or two Gladiator tanks positioned against a wall so Onrush will not knockback them or hit more members, as the other party members position themselves on the sides close to the horns to have a shot at incapacitating them. One or two Conjurers focus on healing and buffing the tank, while the Thaumaturges cycle between their debuffs, as their DoT spells are the primary source of the damage in this battle. Their weapon skill Flashfreeze II is extremely important and is often included in Battle Regimens, as it can incapacitate the Buffalo's legs in a single hit, rendering him defenseless for a few seconds.
As long as the tank keeps provoking the buffalo after each Sonorous Blast, the battle can end quickly and with no deaths.