Verdict: A gothic sapphic monster romance with a genuinely great premise, a magnetic serpent-queen love interest and 5/5 heat, undercut by a 124-page length that leaves most of its plot as an outline.

Best for: Readers who want a femme-dom monster, explicit spice and a man-killing revenge fantasy in one sitting, and who can forgive a romance that goes from captivity to devotion in about a day.

Heat level: ★★★★★ (5/5 — explicit and plentiful)

Rating: ★★★★☆ (3.5/5 — a 3.73 Goodreads average and a 3.59 on StoryGraph, held down by the length almost every reviewer wanted doubled)

Tropes: Captive romance, femme dom, monster romance, gothic haunted manor, Beauty and the Beast retelling, Medusa retelling, age gap, virgin heroine, praise kink, forced proximity.

Lady Venom Takes A Mistress by Kat Blackthorne is a standalone 124-page novella — self-published through the author’s own Dark Hearts Press imprint in September 2023, set in the same universe as her Halloween Boys series but requiring none of it — that runs as a paranormal sapphic romance in a loosely historical setting, where Poesy Laroche escapes a marriage auction into the woods and is claimed as a mistress by the snake-attended monster the villagers call Lady Venom.

It has a 3.73 average across 2,821 Goodreads ratings, a 3.59 across 745 on StoryGraph, and a 4.2 across 1,093 on Amazon — where the book is filed not under Romance but under Erotica. The reviews split harder than 3.73 suggests: 60% of Goodreads ratings sit at four or five stars, and 37% sit at three or below. Both halves of that split are worth understanding before you start.

What Is Lady Venom Takes a Mistress About?

Lady Venom Takes A Mistress is a gothic monster romance and a captive romance, and the two labels carry most of the book’s DNA. Gothic means the haunted estate, the watching flowers, the whispering ghosts and the maze — the manor is a character, and readers say so constantly. Captive means the central power imbalance is the point rather than an obstacle: Lady Venom takes Poesy, tells her there is no escape, and the erotic charge runs through that arrangement rather than around it. romance.io’s users tag the book fem-dom, non-human heroine, abduction and age gap, which is an accurate map of what is actually on the page.

Poesy is introduced through what she has been denied. She is property at auction, promised to a man who has told her plainly he intends to break her, and her only act of authorship is to run somewhere worse. Lady Venom is introduced through what the world assumes about her — a legend, a scream in the trees, a thing to be feared — and the book’s real business is dismantling that assumption from the inside. It is told in first person, which keeps you sealed inside Poesy’s disorientation and means Lady Venom stays unreadable for exactly as long as the plot needs her to.

What Makes This Gothic Sapphic Monster Romance Work

• The premise: A sapphic Medusa crossed with Beauty and the Beast is the element readers name first and most consistently, and even the harshest reviews concede the idea is excellent before dismantling the execution.
• Lady Venom herself: The serpent-attended monster is the reason this book has 2,821 ratings. Readers describe her as mysterious, reserved, witty and genuinely frightening, and she carries scenes the plot does not.
• The revenge fantasy: Every man in the book is a monster and most of them die badly. This lands as catharsis rather than cheap shock, and it is the single most repeated pleasure in the reviews.
• The heat: Rated 5/5 “explicit and plentiful” by romance.io — its top band — and readers treat the spice as the headline rather than the seasoning.
• It commits to the gothic: Snakes, ghosts, poisonous gardens, a cursed estate. The atmosphere is doing real work, and the paranormal furniture is not decorative.

Book Synopsis

Poesy Laroche has spent years sabotaging her own prospects, and it has finally stopped working. The auction is a formality dressed as a ceremony: women are bid on, sold, and delivered to husbands who have already explained what will happen to them. Poesy’s winning bidder has been explicit about his intentions. Her mother is satisfied. There is no version of the day that ends with Poesy free, so she does the only thing left and runs into the forest everyone in the village has spent her whole life warning her about.

The woods belong to a story rather than a person. Screams at night, a manor nobody returns from, a lady made of snakes. Poesy would rather be killed by something beautiful than kept by something ordinary, and she walks in with that calculation intact. What she finds is a maze she cannot leave, an estate where the flowers pay attention and the dead have opinions, and a mistress of the house who looks at her and decides she is keeping her.

Lady Venom is not the legend. She is colder and stranger and considerably funnier than the stories allow, and she is bound to the estate by something Poesy is not told about. The bargain between them is one-sided by design — Poesy has no route out, and no particular wish to find one — and the danger in the manor is not the danger the village imagined. There are ghosts here who died for a reason. There is a curse with an author. And the question underneath the whole arrangement is whether the thing keeping Lady Venom in this house is the same thing that will eventually take Poesy out of it.

My Review

The concept is the best thing here and I want to be clear about how good it is, because everything after this is a qualification. A sapphic Medusa who is also the Beast, running a haunted estate staffed by ghosts and snakes, who takes a woman fleeing a marriage auction and finds she has taken something that bites back — that is a premise worth a full novel, and Blackthorne writes the top layer of it with real flair. Lady Venom is genuinely magnetic. She has the best lines, the best entrances, and a menace the book never softens for the sake of the romance.

The gothic texture is the other real pleasure. The manor, the maze, the watching garden, the ghosts who turn protective when the house is threatened — readers single these out repeatedly, and one Goodreads reviewer calls the writing lyrically beautiful in exactly the passages where the setting is doing the work. The other consistent draw is blunter: every man in this book is vile and most of them are killed, usually by the two women together, and the reviews are full of people who found that specifically restorative. As one Goodreads reviewer put it, her favourite genre might be “lesbians falling in love then killing men together.” That is not a joke about the book — it is an accurate description of what it delivers and why people love it.

Where it struggles is length, and this is not my preference against the crowd’s — it is the single most repeated criticism in the reviews, and it comes from the five-star reviewers as often as the one-star ones. The book is 124 pages, and reader after reader says the same thing in different words: this needed to be a novel. One Amazon reviewer puts the shortfall at another 150 to 200 pages. The consequences stack. The romance is instalove by structure rather than by choice — several readers note the leads are in bed inside about a day, and one describes Poesy’s feelings flip-flopping paragraph to paragraph for the whole book. The lore is sketched and then asserted: how Lady Venom became what she is, why the original bargain protected the ghosts, why a vampire from another of the author’s books is here at all. A one-star reviewer’s verdict is harsh and not entirely wrong — the smut is written and the plot is outlined. Line-level craft draws its own cluster of complaints, with multiple readers calling the prose poorly edited, and a specific recurring flag on the dialogue: a StoryGraph reader and two Amazon reviewers independently note the characters switch between period register and thoroughly modern speech, which pulls the historical setting apart. There is a real minority who love the prose and quote it at length, so this one is taste-dependent — but the register problem is named too often to be dismissed.

One expectation to reset, and it is ours as much as anyone’s, since this book sits at number ten in our own spicy sapphic romantasy guide. Amazon does not shelve it as romance. It sits under Erotica, and its category ranks are in LGBTQ+ Horror and Fantasy Erotica. That is the more honest label. This is a 124-page erotica novella with a gothic fantasy setting, not a romantasy in the sense that a reader coming from a 500-page magic-system book means it. If you want worldbuilding with rules and a slow burn, calibrate hard. If what you want is a monster, a manor and an extremely explicit weekend, this is exactly the right size.

My honest note: A novel’s worth of ideas compressed into a novella’s worth of pages, and you can feel the missing 200. If you read for plot and earned romance, the gaps will be all you see. If you read for atmosphere, a great villainess and heat, it delivers everything it actually promises.

How Dark and Spicy Is Lady Venom Takes a Mistress?

A full 5/5. romance.io rates the steam level “explicit and plentiful,” its top band — the same rating it gives the most explicit titles in the genre — and reader consensus backs it without qualification. Individual reviewers put the spice at 4/5 and 5/5 in their own breakdowns, and the recurring note is that the sex is the most fully realised writing in the book. It arrives early, it recurs, and it is inventively supernatural about what a serpent-monster can do.

The darkness needs naming separately, because it is real and it is front-loaded. romance.io’s users flag dubious consent, abuse and rape on this title, and a Goodreads reviewer warns specifically for attempted rape and sexual harassment. The premise is captivity, the power imbalance is not resolved before the sex begins, and the violence against the male characters is graphic — at least one reviewer who otherwise loved the book describes a particular scene as genuinely difficult to shake off. That said, the tone is revenge fantasy rather than grimdark, and no reviewer I found reports the cruelty being directed at the leads. For more in this register, browse the paranormal and fantasy reviews.

Who Should Read This Book?

You’ll likely love it if: you want a monster love interest who stays monstrous, you read for atmosphere over plot mechanics, you want explicit heat from the first act, and a book you can finish in one evening is a feature rather than a compromise.

You may want to skip it if: instalove ruins a romance for you, you need worldbuilding that explains itself, unpolished prose and modern dialogue in a historical setting pull you out, or you were promised romantasy and will feel short-changed by a 124-page erotica novella.

In short: a superb premise and a genuinely great villainess, delivered at a third of the length the story needed.

What Readers Are Actually Saying (August 2026)

There is no viral moment here and no professional coverage of any kind. I found no Publishers Weekly, Kirkus, Library Journal or Booklist review, and none of the sapphic review blogs — The Lesbrary, LezReviewBooks, Bookish Sapphic, Jude in the Stars, I Heart SapphFic — appear to have covered it. Amazon’s “Editorial Reviews” block looks like trade coverage at a glance but is not: all three pull-quotes are from named Goodreads reviewers rather than outlets. What the book does have is genuine, modest, organic BookTok activity from ordinary reader accounts alongside the author’s own, and one Goodreads reviewer blames BookTok outright for the recommendation. Discovery is otherwise doing the quiet indie thing: a low Kindle price, Kindle Unlimited availability, a bestseller-rank foothold in LGBTQ+ Horror and Fantasy Erotica, and an author-produced audiobook narrated by Calamity Jane Lane, self-released in 2023 with sound design that listeners describe as immersive — the runtime is not published on any retail listing I could reach, and there is no Libro.fm edition. Nearly three years on, it is still accumulating ratings: 172 people were reading it and 4,865 had it shelved as want-to-read on the day I checked.

Why readers love it (according to the discourse): The man-killing, first and loudest — “female rage,” “women’s rights and wrongs” and variations on I like that the men die recur across Goodreads, StoryGraph and Amazon from readers who otherwise disagree about everything. Then Lady Venom as a character, who is admired even in two-star reviews. Then the gothic atmosphere: the ghosts, the snakes, the garden, the manor. The spice is named as a headline feature by almost everyone, including readers who disliked the book. And a real minority praises the prose specifically — quoting lines, calling the imagery lyrical — which is notable, because unpolished writing is one of the loudest complaints. Audio listeners are warm about it too, with one crediting the narrator’s “smooth, husky voice” for the atmosphere.

What readers argue about and complain about: Length, above everything, and unusually it is the same complaint from lovers and detractors. Reviewers at every star level say the book should have been a novel; the phrasing “I wish this had more plot development” turns up in five-star reviews. Second, and downstream of the first: the romance is instalove. Readers note the leads sleep together inside roughly a day, and one describes the emotional arc oscillating paragraph to paragraph rather than building. Third, the lore is asserted rather than explained — how Lady Venom became what she is, why the curse protects the ghosts, why a vampire from another of the author’s books appears at all. Fourth, editing and register: a StoryGraph reviewer calls it “As poorly edited as it is written,” and an Amazon reviewer names the specific mechanism, describing dialogue that switches between Victorian-era and modern English. Fifth, the ending is abrupt; several readers wanted the aftermath the book skips, and the epilogue’s transformation reads to some as a shortcut to the happy ending. The genuine split is on the prose: a substantial minority find it quotable and atmospheric where the majority find it rushed, and one five-star reviewer cheerfully calls the writing atrocious while giving it full marks anyway. Worth noting against all of this: StoryGraph’s did-not-finish rate is only 2%, well under the rates I have been seeing on longer titles this month. People are not bouncing off this book. They finish it, and then they wish there had been more of it.

The standalone question worth asking first: it resolves completely. Poesy and Lady Venom get a happily-ever-after, there is an epilogue, and nothing is required before or after it — the Halloween Boys crossover is flavour, not homework. No sequel has been announced as of August 2026, despite a steady stream of reviews asking for one. If you want more of this author, the honest picture is that this is her lowest-rated widely-read title: Lady Venom sits at 3.73 across 2,821 Goodreads ratings, while her most-read book, Ghost, holds 4.04 across more than 11,000. Among her other sapphic titles, Selah Gothic rates 3.94 across roughly 1,600 ratings and sWitch sits level with this one at 3.73. Go to Ghost for the strongest reception and to Selah Gothic for the nearest sapphic gothic neighbour.

Frequently Asked Questions

Does Lady Venom Takes a Mistress end on a cliffhanger?

No. It is a complete standalone with a happily-ever-after and an epilogue. Some readers find the final chapters abrupt and wish for more aftermath, but you are not left hanging and no sequel is required.

How spicy is Lady Venom Takes a Mistress?

A 5/5. romance.io rates it “explicit and plentiful,” its top band. The scenes are graphic, supernaturally inventive and arrive early, and readers across every rating level name the spice as the book’s strongest element.

Do I need to read The Halloween Boys first?

No. It shares a universe and some crossover lore, and one side character comes from those books, but the publisher’s own description confirms no prior reading is needed. Several readers found that crossover character confusing precisely because they had not read the series.

Is it actually romantasy?

Not in the way most readers mean. Amazon files it under Erotica, with category ranks in LGBTQ+ Horror and Fantasy Erotica, and it runs 124 pages. It is a gothic monster erotica novella with fantasy furniture rather than a plotted fantasy romance.

Is there an audiobook?

Yes — narrated by Calamity Jane Lane and self-released by the author in 2023, with sound design that listeners repeatedly describe as immersive. No runtime is published on the retail listings, and there is no Libro.fm edition.

What are the content warnings?

romance.io’s users flag dubious consent, abuse and rape; a Goodreads reviewer adds attempted rape and sexual harassment. Expect captivity, a power imbalance treated as erotic, graphic on-page killings of male characters, and snakes throughout.

If You Loved Lady Venom Takes a Mistress, Read These Next

Readers who want the captive dynamic taken seriously at full length land most often on Captive in the Underworld by Lianyu Tan, which runs the same power imbalance far darker and with none of the softening. If the fairy-tale bones are the draw, Bitterthorn by Kat Dunn is the sapphic Beauty and the Beast with room to actually build the isolation. And for the same 5/5 heat band inside a plotted fantasy novel, Her Spell That Binds Me gives you the explicit sapphic romantasy this book is shelved beside but does not quite belong to. Browse the paranormal and fantasy lesbian romance collection or the full Book Reviews archive for more.

The Bottom Line

Lady Venom Takes A Mistress is a book with a novel’s ambition and a novella’s page count. The premise is excellent, Lady Venom is a genuinely great monster, and the heat delivers exactly the 5/5 it is rated. It is also structurally rushed, built on lore it never explains, and carrying a romance that resolves before it has earned anything. Whether that trade works depends entirely on what you came for — but at 124 pages the cost of finding out is low, and StoryGraph’s 2% did-not-finish rate says almost nobody regrets starting. Check Lady Venom Takes a Mistress on Amazon →

The Eikna Overall Ranking

On the Eikna scale, Lady Venom Takes a Mistress ranks as a high-concept indie gothic erotica novella — atmospheric and genuinely cathartic, hollowed out by its own brevity, and best approached for the monster and the heat rather than the plot.

The Evidence Scorecard

Overall ★★★★☆ 3.5/5

• ✓ 3.73 average across 2,821 Goodreads ratings
• ✓ 3.59 on StoryGraph, 4.2 on Amazon
• ✓ Only 2% did-not-finish on StoryGraph
• ✓ 37% of Goodreads ratings are three or below

Romance ★★★☆☆ 3.4/5

• ✓ Femme-dom dynamic genuinely charged
• ✓ Banter between the leads widely praised
• ✓ Devotion arc lands for most readers
• ✓ Instalove named across every rating level

Characters ★★★★☆ 3.5/5

• ✓ Lady Venom admired even in negative reviews
• ✓ 75% call the characters loveable on StoryGraph
• ✓ Poesy keeps a spine under captivity
• ✓ 30% say character development is weak

Writing ★★★☆☆ 3/5

• ✓ Gothic imagery is the strongest craft element
• ✓ A real minority quote the prose admiringly
• ✓ Sex scenes are the most fully written passages
• ✓ Editing and period-versus-modern dialogue flagged repeatedly

Emotional Impact ★★★★☆ 3.6/5

• ✓ Revenge catharsis is the most-named pleasure
• ✓ The auction opening genuinely stings
• ✓ 85% of StoryGraph readers mark it dark
• ✓ Stakes undercut by unexplained lore

Heat Level ★★★★★ 5/5

• ✓ romance.io top band, explicit and plentiful
• ✓ Explicit from the first act onward
• ✓ Inventively supernatural rather than generic
• ✓ Dubious consent and abuse flagged by users

Ending ★★★☆☆ 3.3/5

• ✓ Complete standalone, no cliffhanger
• ✓ HEA delivered with an epilogue
• ✓ Epilogue twist praised by some readers
• ✓ Repeatedly described as abrupt and rushed

Re-read Value ★★★★☆ 3.6/5

• ✓ 124 pages makes a revisit cheap
• ✓ Immersive audiobook is a strong second pass
• ✓ Quotable lines readers return to
• ✓ Thin plot leaves little to rediscover

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