Could a Warlock 14 use Create Thrall on another character they play?

@JeremyECrawford Could a Warlock 14 use Create Thrall on another character they play? As written doesn't say NPC. Maybe use downtime days?

— Joseph Bridgewater (@JOSEPH91304707) October 25, 2016

Create Thrall works on an incapacitated humanoid. The feature doesn't care who's playing that humanoid. #DnD https://t.co/XuolmusJ4b

— Jeremy Crawford (@JeremyECrawford) October 25, 2016