With so much experience in rehab, this "warlock"—Sheen's word choice, not ours—might as well be an expert on recovery.
Alas, Charlie Harper might be dead, but the warlock lives on.
I choose my favorite New Mutants character for the lady in the Nightcrawler T-shirt (warlock, for the record).
Old English wærloga "traitor, liar, enemy," from wær "faith, a compact" (cf. Old High German wara "truth," Old Norse varar "solemn promise, vow;" see very; cf. also Varangian) + agent noun related to leogan "to lie" (see lie (v.1)).
Original primary sense seems to have been "oath-breaker;" given special application to the devil (c.1000), but also used of giants and cannibals. Meaning "one in league with the devil" is recorded from c.1300. Ending in -ck and meaning "male equivalent of a witch" (1560s) are from Scottish.