Atramentium: The Sanguine Duology

by Claudia J. Filusch

In the dark streets of Chantemerle, France, a city of mist, candlelight, and crumbling architecture, alchemist Kurou pursues a power that should never be touched. Obsessed with the mysterious substance Atramentium, he drifts further from the man he once was.

Only Rin can see the humanity still buried beneath his fevered ambition. But in Chantemerle, where people whisper, mirrors reflect more than reality, and every alley hides secrets. Even love may not be enough to save him—or her—from the darkness rising between them.

When obsession and sacrifice collide, the lines between brilliance and madness, loyalty and betrayal, are drawn in fire and shadow.

289 pages, Paperback

Published December 1, 2025

About the author

Claudia J. Filusch is a German-Polish author, writing sci-fi fantasy and dark fantasy stories that explore the boundaries between worlds—whether ancient, or internal. With a background in art history, English literature and linguistics, she brings a layered, atmospheric style to fiction, weaving language and lore into richly imagined universes.

When not writing, Claudia is probably reading something dystopian, sketching story concepts in the margins of notebooks, or drinking a good cup of tea.

Her debut novel, Echo’s End, is a haunting blend of mystery, myth, and momentum—perfect for readers who like their fantasy speculative and their sci-fi soaked in shadows.

Reviews

[Effy · Rating 5 out of 5]

I think I’ve made myself clear as a huge fan of Claudia and her work. But when I say THIS IS HER NICHE, I hope you understand what I mean!! This is a gothic horror unlike anything I’ve read before. It was haunting, gritty, dark and tense in all the right places. A brilliant alchemist consumed by obsession and hubris, a woman who tries desperately to bring him back to the light, but shattering the role of a quiet, 2D, love sick woman. She has agency, she has goodness and she does what needs to be done, even if the chances of success are bleak. I absolutely loved this story! The pacing is fast and pulls you in immediately, the characters are nuanced and complex, the setting in Chantemerle, France is dark and misty, plagued by illness and other…unseen forces and creatures alike. Alternatively, the writing is superb. It’s so clear how much Claudia has refined her craft as well as stepped into a niche that fits her like a glove. I was simply along for the ride while reading and enjoyed every second of it.

I FLEW through this book, and if you’ve been looking for a fun, quick, pocket-sized gothic horror, then this one is for you!! The physical copy is adorable, making a sharp contrast to the content, but it’s also available on KU!!

[witchy_book_babe · Rating 3 out of 5]

Really bummed that this didn’t meet all of my expectations. I think the first half was relatively strong, there were minor grammatical mistakes and some areas that I was getting a bit lost in….but, I felt secure in the first half that I was going to love this book.

However, the writing did seem to weaken the further on I read. Here are the main culprits of why this wasn’t the book for me:

Uncorrected Errors:
-Sentences missing a period.
-Sentences that were missing a space between the period and next word of the beginning of a new sentence.
-Multiple instances of a sentence ending with a word, then a period, and either an ‘m’ or ‘n’ (Example: “____.m”).
-There were entire sentences that must have been cut and pasted, but the author maybe forgot to delete it from the earlier passage (Example: I would read Paragraph A to then read Paragraph B with a direct duplicate of a line used in Paragraph A).
-A LOT of scenes had me feeling like I was missing pages of explanation. Character movements seemed like a cd skipping you know?
-To piggyback on what I said above ^ there was also a scene where Rin did not have her necklace, then she had the necklace, then Kurou looks around the room and sees the necklace on the nightstand…this all happened relatively close together in the final chapters and something I think that should have been caught.

The substance didn’t really get enough time to be explored. I would have loved more Alchemy research being explained.
-What really was Kurou learning from it?
-How was he planning to use it? Was he thinking of replicating it? Making doses? That never really was addressed.

The ending was also a question mark for me. Why. I was left wondering why that was the outcome. If there were more breadcrumbs to allow me to see why that outcome occurred then I would be curious enough to read the second book. However, I sadly am not going to move forward with the next installment.

[sam]

dnf 58% // somewhere between a 2 and 3 star. as a 40-50 page short story this could've been great. i feel like the author wanted to create a vibe first plot second gothic horror but i didn't find this atmospheric or immersive at all. mist, fog and grey does not make something a gothic. i'd argue this is closer to a dark academia with the dark, foreboding and obsessive pursuit of knowledge.

i found the prose incredibly repetitive, dense and ultimately uninteresting. lots of cliches “his throat tightened” / “her body softened.” almost a dozen moments of lips curling and curving. "faint, almost imperceptible curl of his lips" literally why. almost twenty moments of eyes and gazes softening. waxing poetic but with not much substance. every single emotion apparently had to cause a specific body part to contract, drop, twist, clench, tighten, flutter, or soften.

thematically, i believe, there was going to be some lovely meditation on choosing yourself and self destruction in the name of saving others but this is becoming too frustrating of a reading experience for me to continue what could potentially be really interesting tones and themes.

i'm really interested in this author so i will be trying her work again.