A warlock is defined by a pact with an otherworldly being. Sometimes the relationship between warlock and patron is like that of a cleric and a deity, though the beings that serve as patrons for warlocks are not gods. A warlock might lead a cult dedicated to a demon prince, an archdevil, or an utterly alien entity—beings not typically served by clerics. More often, though, the arrangement is similar to that between a master and an apprentice. The warlock learns and grows in power, at the cost of occasional services performed on the patron’s behalf.
The magic bestowed on a warlock ranges from minor but lasting alterations to the warlock’s being (such as the ability to see in darkness or to read any language) to access to powerful spells. Unlike bookish wizards, warlocks supplement their magic with some facility at hand-to-hand combat. They are comfortable in light armor and know how to use simple weapons.
Warlocks are driven by an insatiable need for knowledge and power, which compels them into their pacts and shapes their lives. This thirst drives warlocks into their pacts and shapes their later careers as well.
Stories of warlocks binding themselves to fiends are widely known. But many warlocks serve patrons that are not fiendish. Sometimes a traveler in the wilds comes to a strangely beautiful tower, meets its fey lord or lady, and stumbles into a pact without being fully aware of it. And sometimes, while poring over tomes of forbidden lore, a brilliant but crazed student’s mind is opened to realities beyond the material world and to the alien beings that dwell in the outer void.
Once a pact is made, a warlock’s thirst for knowledge and power can’t be slaked with mere study and research. No one makes a pact with such a mighty patron if he or she doesn’t intend to use the power thus gained. Rather, the vast majority of warlocks spend their days in active pursuit of their goals, which typically means some kind of adventuring. Furthermore, the demands of their patrons drive warlocks toward adventure.
The Archfey
Such a barbarian might be inhabited by a primal spirit or be descended from shape-shifters.
The Fiend
You have made a pact with a fiend from the lower planes of existence, a being whose aims are evil, even if you strive against those aims. Such beings desire the corruption or destruction of all things, ultimately including you.
The Hexblade
You have made your pact with a mysterious entity from the Shadowfell — a force that manifests in sentient magic weapons carved from the stuff of shadow. The mighty sword Blackrazor is the most notable of these weapons, which have been spread across the multiverse over the ages. The shadowy force behind these weapons can offer power to warlocks who form pacts with it. Many hexblade warlocks create weapons that emulate those formed in the Shadowfell. Others forgo such arms, content to weave the dark magic of that plane into their spellcasting.
Because the Raven Queen is known to have forged the first of these weapons, many sages speculate that she and the force are one and that the weapons, along with hexblade warlocks, are tools she uses to manipulate events on the Material Plane to her inscrutable ends.
The Celestial
Your patron is a powerful being of the Upper Planes. You have bound yourself to an ancient empyrean, solar, ki-rin, unicorn, or other entity that resides in the planes of everlasting bliss. Your pact with that allowing you to experience the barest touch of the holy light that illuminates the multiverse.
Being connected to such power can cause changes in your behavior and beliefs. You might find yourself driven to annihilate the undead, to defeat fiends, and to protect the innocent. At times, your heart might also be filled with a longing for the celestial realm of your patron, and a desire to wander that paradise for the rest of your days. But you know that your mission is among mortals for now, and that your pact binds you to bring light to the dark places of the world.
The Genie
You have made a pact with one of the rarest kinds of genie, a noble genie. Such entities rule vast fiefs on the Elemental Planes and have great influence over lesser genies and elemental creatures. Noble genies are varied in their motivations, but most are arrogant and wield power that rivals that of lesser deities. They delight in turning the table on mortals, who often bind genies into servitude, and readily enter into pacts that expand their reach.
The Undying
Death holds no sway over your patron, who has unlocked the secrets of everlasting life, although such a prize—like all power—comes at a price. Once mortal, the Undying has seen mortal lifetimes pass like the seasons, like the flicker of endless days and nights. It has the secrets of the ages to share, secrets of life and death. Beings of this sort include Vecna, Lord of the Hand and the Eye; the dread Iuz; the lich-queen Vol; the Undying Court of Aerenal; Vlaakith, lich-queen of the githyanki; and the deathless wizard Fistandantalus.
The Fathomless
You have plunged into a pact with the deeps. An entity of the ocean, the Elemental Plane of Water, or another otherworldly sea now allows you to draw on its thalassic power. Is it merely using you to learn about terrestrial realms, or does it want you to open cosmic floodgates and drown the world?
Perhaps you were born into a generational cult that venerates the Fathomless and its spawn. Or you might have been shipwrecked and on the brink of drowning when your patron’s grasp offered you a chance at life. Whatever the reason for your pact, the sea, and its unknown depths call to you.
Entities of the deep that might empower a warlock to include krakens, ancient water elementals, godlike hallucinations dreamed into being by kuo-toa, merfolk demigods, and sea hag covens.
The Great Old One
Your patron is a mysterious entity whose nature is utterly foreign to the fabric of reality. It might come from the Far Realm, the space beyond reality, or it could be one of the elder gods known only in legends. Its motives are incomprehensible to mortals, and its knowledge so immense and ancient that even the greatest libraries pale in comparison to the vast secrets it holds. The Great Old One might be unaware of your existence or entirely indifferent to you, but the secrets you have learned allow you to draw your magic from it.