One of the great things about Dragon Heist is that it has some replayability value to it (more so on the DM's end of things than the player's, but that's neither here nor there), and How Malar Stole Midwinter! only increases that replayability, adding a new, more sinister villain option to the roster.

The villain presented in this supplement is Lady Victoria Vladikoff, a minor Waterdhavian noblewoman that - pardon the pun, or don't in this case - moonlights as the leader of a lycanthropic cult devoted to Malar the Beastlord, god of bestial savagery and bloodlust.

So, the supplement comes with information on how to integrate Lady Vladikoff into the module itself, including information on her goals, how she relates to the Galhund's and the Nimblewright, additional info on the vault keys, an encounter chain, what happens if your players kill her, how her plans can be disrupted, and what occurs if she succeeds.

That last point is a big one for me, because Lady Vladikoff's goal is ultimately to bring a religious, ritualistic Most Dangerous Game styled hunt to Waterdeep every season, and it honestly makes her a more terrifying villain compared to say, the Xanathar's comedic villainy.

Oh, the Dr. Seuss thing? Like, yeah... it's there. Not super prominently mind you. The references aren't as subtle or as plentiful as I would like, but at the same time I suppose that keeps it from being too obnoxious for people who might not dig the sillier aspects that something as weird as a Dr. Suess/D&D mix brings. There are some pretty direct refrences by way of names, and some rhyming messages to intercept.

The supplement also includes a map of the Vladikoff Estate which is relatively similar, if a bit smaller, than the Cassalanter Estate. The map is also by Dyson, so if you are among those that enjoyed their inclusion in Dragon Heist, you'll be delighted because this really does look like it came straight out of the module itself.

One big thing I'd note as a problem for the supplement is that the main villain herself is not very strong. She is a modified Werewolf (CR 3) with a few boosts that would increase her CR by... a little, but ultimately she is absolutely too easy to kill, and a party from level 3-5 would probably wipe the floor with her unless she manages to get all her allies to her side asap, and even then. Her being this weak is not really in the spirit of Dragon Heist (the next weakest villain would be Lady Cassalanter, a CR 5 9th level wizard who is generally going to be found with her CR 10, 15th level cleric husband). I would strongly recommend replacing Lady Vladikoff's stats with something more appropriate (I would personally recommend the Werewolf Alpha from Monster a Day on reddit, while retaining her mental stats and special calling howl ability from the supplement, and removing one or two of the Alpha's three legendary resistances).

Other than that, the only thing I wish the supplement provided was artwork of Lady Vladikoff out of her werewolf form, but maybe when the supplement has made more money the creator can provide that!

Ultimately I definitely recommend How Malar Stole Midwinter! and I can say for certain that when I run Dragon Heist, I'm far more likely going to use this supplement over any of the four villains presented in the module itself. I continue to find myself amazed by how great the villain supplements are on the dmsguild thus far, and I hope How Malar Stole Midwinter! gets to be just as popular as Waterdeep Unseen, because it really does bring a lot to the table that I believe both you and your players would enjoy, especially if it ends with them being victims of Malar's High Hunt...