@Mr. Death
I started this thread with the thought that it could be Nic who kills Maggie with his entropy curse, but just to play devil’s advocate, you’re assuming that Lord Raith had just the one entropy curse up his sleeve. Also as the King of a nation of vampires, I’m sure through his Court he could get as many mortals to sacrifice as he needs. I mean people like Madeline seem to drain a person every day or couple of days. Can you imagine what the entire WCV goes through daily?
I think it's the main one we've seen and it's a very powerful curse, the kind of thing that he'd need/want to get to a powerful wizard. Plus, the HWWB connection is too good to pass up.
Madeline is noted as being something of an out-of-control loose cannon. Others, like Lord Raith and Lara, tend to drag it out for weeks or even months, based on their dialog, and they disapprove of how Madeline treats her prey based on White Night.
But for the White King to go through a person a day, that'd be up there with the Red King's near-junky tendencies. It'd be a sign of weakness.
And if he sacrifices that person a day to try and kill another person -- and keeps
failing to do so -- that's yet more weakness.
And while I'll agree that Nic
could have killed Maggie, I just don't see him wanting to, or a good motive for it.