- The first encounter in Gruul's lair is one Lair Brute that patrols up and down a long cavern. After him are two other randomly spawned mobs, either Brutes or Gronn-Priest. The patrol can be pulled single, but the duo beyond must be done together. The first mob will call for help, but tanked next to the portal he will be too far to be heard by the next two mobs.
- If only one of the pair of two mobs is killed, they will both respawn.
- The mobs leading to High King are on a 1 hour timer.
- When High King Maulgar is killed the gate on the far side of him will open and the mobs leading to him will no longer spawn.
- When the gate is opened, there will be several mobs inside. All static packs are randomly Gronn-Priests or Lair Brutes. The two patrolling mobs are always Brutes.
- First pull is a double pull.
- Second pull is a single pull that patrols from the first double pull to the fire.
- Third pull is a double pull by the fire.
- Fourth pull is a single patrol that leads from Gruul's area to the fire.
- The last pull is a triple pull at the end of cavern that leads to Gruul.
- When Gruul is killed no mobs will spawn inside of his lair.
- Main article: Gruul's Lair loot
There are 6 Unstable Flasks available designed especially for fighting Gruul.