| Category | Liquids |
| Type | water |
| Source | Lethe |
| Cost | 1,500 GP / ounce |
A thousand years into the Creation War (1486 DE - 8777 DE), the system of Ellubôz had become better known as the Forge Worlds. The nine core worlds of the system were places of war preparation, entirely devoted to building armies, arms making and experimentation of all sorts. The changing of the Lethe river came about from one of these experiments. Cross-breeding of alien water lilies with those native of the river Lethe resulted in a malign sentience that fed on the memories of those nearby. As these plants decayed, they made the water around very dangerous to drink. After several millennia of this, it was so concentrated that it made one ignorant to all that had transpired. The Covenant found ways to get around the river's sentient water lilies, putting the waters of the Lethe to use. Alchemists found a way to dilute it, making elixirs that could erase the recent memory of those enticed to drink it.
In its purest form, water of the Lethe causes forgetfulness. When Asmodeus and Dispater were making their devil legions, they designed them to be immune to Lethe's forgetfulness.