I’ll go first.
A person seeks out a fey to get a warlock pact. The person doesn’t know, however, that they’re a sorcerer with strong fey ancestry that just hasn’t manifested yet. The fey obviously agrees to the “pact” and makes a ridiculous contract that the person agrees to. The person lives their entire life believing they’re a warlock when they’re actually a sorcerer. The only thing the fey did was help the person’s magicky shit manifest.
What would that be mechanically? Warlock?
Yep, hexblade. A warlock who doesn’t know he’s a warlock. Spellcasting is just yelling loudly, and I’d choose spells that could be explained as him just being really scary.