Absolutely! The Player’s Handbook warlock class writeup doesn’t go especially deep on all the possible nuances of patron/warlock relationships, but it does mention that you might be at odds with your patron, and the patron/warlock bond can come about without consent on either side. This is the central fiction of Changeling: the Lost, from which the Captive is derived; in that game, you’re a mortal who was abducted, kept as a prisoner and laborer for a time, and eventually escaped. Because of the changes you experience from this Durance, you can tap into various Fae contracts. To translate that into D&D-speak, you discover that they MADE you a warlock.

Once you’ve made that leap, well, the fiction necessary to explain a Changeling warlock is even simpler. Fey magic literally constructed you from nothing more than sticks and leaves – is it any surprise that you can direct some of that power to your own ends?

Ditto on that. Generally the Changeling Background is awesome, as it is not actually just a Background, it can also apply for a proxy sub-race as well.

Should be PLENTY of angst and roleplaying grist there. 🙂