In the room after swimming through the tunnel in Abazigal's Lair, there is a pool of liquid. When I check it out I get the response: "An empty Breath Potion Flask is needed to gather the liquid." Where do I find this item? If it means I need to be in possession of a breath potion, I have not found one throughout TOB.

It is loot from the WereWyern you meet at the pools area. Go back to where you defeated the WereWyern, and press your <font color="cyan">Tab</font> key to highlight the loot.