5E Warlock Subclass: The Great Wyrm

From publisher blurb: Worship of the creatures known as the Great Wyrms is not something one should boast of. The beings are known all over the world, but by different names. To some, they are Voidserpents, ever-consuming of the energy that lies between the planes. To others, they are Wish or World Snakes, long enough to reach all around the world and bite their own tails. The danger of these creatures is well-known, and one should try to be strong against their temptations.