On Toril, the Primordials existed before the Gods, and were banished by them to the Elemental Chaos. Also known as the Dawn Titans, these beings of elemental energy are more than powerful enough to grant boons and powers to would-be warlocks. A Primordial Warlock might be the leader of an elemental cult, the protector of a town or village beset by natural disasters, or even a templar dedicated to ensuring that natural order is maintained.
Several Primordials managed to avoid this banishment, such as the five Elemental Lords and even Ubtao, the Deceiver. Whether your power comes from one of these more physically accessible primordials, or from one within the Elemental Chaos, these warlocks are granted various abilities and spells centered around elemental magic.
Primordial Warlocks can be of any alignment, though their association with Primordials tends to make them more chaotic than most. Choose the Primordial Patron if you want a Warlock that specializes in elemental magic, and is capable of dealing exceptional damage as a 'striker'. Avoid this subclass if you're looking to play a Warlock with expanded spells, or a focus on weapons and armor.
This subclass was inspired by the Primordials of the Forgotten Realms, but you can easily fit it into just about any world that has elemental magic.
- from the publisher's blurb