A morally ambiguous and self-serving girl (grey!oc) reincarnates as Lily Evans's twin sister, Tansy Evans. (Disclaimer(s) here: J.K. Rowling owns the Harry Potter franchise.)

Alexander Graham Winslow -that's a mouthful- disappointingly dies in an accident due to an accident. Consequently, when The Lord's -who?- negotiation department arrives, he finds himself mindlessly agreeing. The part where he is plopped like a dingus into the Harry Potter world is unexpected. Unexpected but welcome.