Vashj Sis

Within the whole Instance Dungeon, this Boss was of intermediate difficulty. Unlike Leotheras the Blind and the Fathom-Lord Karathress, he didn't drop T5 pieces. This made his value the same as Hydross the Unstable, but a bit lower than the two bosses that dropped T5 equipment.

If they could kill the first boss, then they should pretty much be able to fight Morogrim Tidewalker.

Resistance equipment wasn't necessary, nor was an HP with a full buff up to 9K, but it could guarantee that after a team member went through the Water Tomb, wasn't able to heal in time and got damage from an earthquake, they would still be able to survive and thus reduce the difficulty of fighting.

This Boss's signature skill was Water Tomb.