Devil You Know

Diamond Devils #3

by Harmony West

Juliet

Only a psycho would fall for a masked stranger. But that’s exactly what I am.

We met at a haunt, where he chased me down and made me feel things no stranger should. I confessed too much to him, and now he’s going to make all my darkest fantasies come true.

He follows me back to campus, but I can’t afford to have a stalker. Not when I need to take justice into my own hands. I’m not stopping until I’ve gotten my revenge on every single one of them, and I won’t let anyone stop me.

Trey

In the dark, I haunt her. But in the light of day, she doesn’t know I’m the man beneath the mask.

Juliet Hayes is just as insane as I am—the little psycho who hunts monsters. And I’m all too happy to help her. We’ll rip our demons apart together.

I’ll be the unhinged Romeo to her psycho Juliet.

Devil You Know is the third installment in the Diamond Devils series and is best suited for mature readers with a taste for unhinged psychos, spice, and revenge fantasy.

Genres: Dark Romance, Hockey, Dark, Romance, Sports Romance, Sports, Smut

272 pages, Kindle Edition

Published February 27, 2025

About the author

Harmony West writes dark forbidden romance. She enjoys her love stories with a side of mystery, twists, and spice.

For updates on Harmony West’s latest releases, visit her website at https://www.harmonywestbooks.com/.

Reviews

[Harmony West · Rating 5 out of 5]

Devil You Know is the third installment in my Diamond Devils series featuring masked hockey men. Juliet Hayes is out for revenge—and Trey Lamont is exactly the unhinged psycho she needs to help her get it.

You can read Devil You Know for FREE with Kindle Unlimited! Paperbacks are available at most major online retailers. If you want a signed copy, you can also order it on my website. 🖤

To stay up to date on all my books, follow me on Instagram, TikTok, and YouTube at authorharmonywest or sign up for my newsletter.

Devil You Know follows Trey Lamont and Juliet Hayes. Their story is full of unhinged spice, masks, obsession, suspense, mystery, and revenge. While I highly recommend reading the series in order, you can skip If You Dare and Drown in You and still enjoy this book.

Tropes include:

- Unhinged psycho
- Mutual stalking
- Masked man
- Black cat FMC
- Biker MMC
- Touch her and die
- Possessive/obsessive hero
- Primal play, blood play, knife play, and breath play

Content warnings: Explicit sexual content, dubcon/noncon, somnophilia, bondage, murder, grooming of minors, graphic violence, revenge fantasy, drugging, public sexual activities, genital mutilation, decapitation, terminated pregnancy (off page), and SA (not explicit).

If you choose to read Devil You Know, thank you for taking a chance on this series! If you are a fan of unhinged psycho romance, I truly hope you enjoy this one!

We have (at least 👀) one more book left in this series, so if you enjoy why choose, be sure to add Die for You to your TBR! 🖤

[Brittany (Brit.tea.reads) · Rating 4 out of 5]

Lol, I did not think Trey could redeem himself. You’ll know what I mean if you’ve read the others in this series. 😆
I was obsessed with him and Juliet. Omg yes, I love it when the FMC is unhinged, too!
Oh, she gets her revenge. She does something to his 🍆 😂, but you’ll have to read to find out.
These two were everything he found his perfect match! 😈🖤

I can’t believe we are almost at the end of this series. It’s been such a hot, wild time, and I can’t wait to read the fourth and final book in this series. I love it.

[astarion's bhaal babe (wingspan matters)]

I've read some fucked up shit over the years, but this...this is on its own level of fucked-uppery.
He's toxic, she's unhinged, they're both problematic and damaged, and the list of trigger warnings and dark themes presend in this book is longer than my infinite tbr.

AND I LOVED EVERY SECOND OF IT.


(RTC but also maybe not because this freaky and kinky little book left me completely speechless.)

[Kate V · Rating 4 out of 5]

3.5 - 4 stars!

Devil You Know is the third book in this series and it follows Juliet and Trey. Juliet is determined to not only get revenge for the wrongs she’s been dealt but to prove that no man can match her dark. Trey has as many demons as Juliet does and when he sets his sights on his little demon sparks fly.

“You’ve found your devil, little demon. You’ve found the black heart that matches yours. We don’t have to set the fires on our own anymore. We can burn it all down together.”

Juliet and Trey incinerated everything they touched with their chemistry and loyalty. Juliet was one badass chick but I really liked her vulnerability with Trey. And Trey? That man was psychotic but in the sexiest hockey god way. Twisty and suspenseful, the plot kept me guessing. This was dark and kinky so mind the triggers but I was here for their hard earned HEA.

[Erica · Rating 5 out of 5]

“Your darkness and mine? They match.”

[Luna ♡ · Rating 3 out of 5]

»You've found your devil, little demon. You've found the black heart that matches yours. We don't have to set the fires on our own anymore. We can burn it all down together.«

★ ★ ★

❥ 𝑱𝒖𝒍𝒊𝒆𝒕 𝜗𝜚˚⋆
She was a psycho and the perfect match for Trey.

❥ 𝑻𝒓𝒆𝒚 ࣪⋆✮
He is a walking red flag.

✥ 𝒕𝒉𝒆 𝒃𝒐𝒐𝒌
This was an okay read. The kinks were too much for me (cause I‘m not into that stuff) and there was A LOT of kinky smut so a lot of the book was not my taste. It was well written and I liked the fresh ideas of the author. It is dark romance and you should really read the trigger warnings!
Juliet and Trey both are psychopaths and a perfect match. Both had a traumatising past which plays an important role in the book.
I skimmed a lot of pages (mostly the smut to be honest) but it still was an okay read.

𝐰𝐨𝐮𝐥𝐝 𝐈 𝐫𝐞𝐜𝐨𝐦𝐦𝐞𝐧𝐝 𝐭𝐡𝐢𝐬 𝐛𝐨𝐨𝐤?
Maybe, if you‘re into dark kinks.

𝐫𝐚𝐭𝐢𝐧𝐠 𝐨𝐮𝐭 𝐨𝐟 𝟓 ׂㅤ𐙚 ࣪ ⭒
plot: 3/5
spice: 3/5
humor: 3/5
couple/tension: 4/5
world building: 5/5
happy end?: yes

𝐭𝐫𝐨𝐩𝐞𝐬 ᡣ𐭩ྀི₊ ⊹
possessive and protective hero, college, masked man, psychopath, hockey romance, dark romance, he falls first, forced proximity, stalker, revenge games, dislike to love, black cat fmc, touch her and die

𝐬𝐚𝐟𝐞𝐭𝐲
ages: both in their early twenties
cheating: no
sharing: no
kinks: primal play, breath play, knife play, blood play, fucks her while she is unconscious, he tattoos her and she pierces his dick (without consent)

𝐬𝐞𝐫𝐢𝐞𝐬 𝐫𝐚𝐭𝐢𝐧𝐠𝐬
#1 If You Dare ★ ★ ★ ★
https://www.goodreads.com/review/show...
#2 Drown In You ★ ★ ★ ★
https://www.goodreads.com/review/show...
#3 Devil You Know ★ ★ ★
https://www.goodreads.com/review/show...

[Tyler | bookishwithty · Rating 5 out of 5]

Devil You Know by Harmony West might just be my favorite book in the Diamond Devils series! Harmony west really outdid herself with this story! I rellllly liked the tropes in this book; Juliet is my kind of girl, and both share the same taste of kinks… and oh my goodness, Trey is simply delicious. I couldn't put this story down and finished it in one sitting. As always, five stars for Miss West!

[Olivia Lupton · Rating 1 out of 5]

A light 2am read 😅

[destiny · Rating 5 out of 5]

“two demons sent from hell to find each other”

I’M GOING FUCKING FERAL FOR JULIET AND TREY HOLY FUCK 😮‍💨

harmony west supremacy 🙌🏼 thank you so much for taking me into your team and giving me this chance to arc read !! i’m so in love with this series and all the characters.

i just knew juliet was going to be a firecracker and trey the misunderstood unhinged villain ❤️‍🔥 wow. these two are fucking electric 🤩 i loved everything about them. when juliet was introduced in the previous book i already knew i was going to be unleashing my new personality. and trey 🧎🏻‍♀️ i may need to schedule myself a lobotomy appointment because HOLY HELL AND I OBSESSED !!!

this is a dark hockey romance, masked man, feisty fmc, trauma, sexual assault, revenge, they stalk each other, biker, fast paced, somno, primal play, knife play, blood play, noncon, dubcon, third book in the series, and dual pov 🏒🖤

the storyline was absolute perfection 🤌🏼 i was hooked from the very beginning !! this series just gets darker and spicier and i’m all here for it 🥵

the obsession and chemistry between juliet and trey is so gripping !! i love them so fucking much 🫀 they both share the same kinks and the both bite back. the way they helped each other through their traumas was something so beautiful i literally cried. they deserve to be heard. they deserve to be understood. there was such unhingeness mixed with sweetness that it just tugged at my heartstrings.

they’re so raw and real. they are absolutely the definition of “couples who slay together stay together”.

🌶️🌶️🌶️🌶️

[Becky Parker · Rating 4 out of 5]

This was better than I thought it was going to be. Dark romance based on trauma.

I could see what was coming and so I wasn't shocked with the big reveal. However, I did love Trey and Juliet. Their characters were perfect for eachother.

Both characters had been SA'd when they were younger and the writer explored this very well I thought.

For me, this lost a star because it was predictable and I could see what was coming otherwise, I enjoyed this.

[Kimber Ann · Rating 5 out of 5]

So much more than I could have hoped for. The vibe was very girl w the dragon tattoo meets Charlie donella’s girl that was taken mixed together. The smut was so unhinged and spectacular, that plot was fucking incredible, tied off in the perfect bow at the end w no unanswered questions of what happened or who was who.

[Dru · Rating 5 out of 5]

⭐️⭐️⭐️⭐️.5
🌶🌶🌶🌶
🔥🔥🔥🔥

Five stars, no question. This book was such a ride, and I loved every second of it. The romance was absolute fire, the kind that jumps off the page and keeps you glued to see what happens next. Juliet and Trey's brand of crazy just worked, and instead of feeling over the top, it made them that much more perfect for each other. The chemistry was intense, messy in all the best ways, and had me rooting for them the whole time.

What I really loved was how their past trauma tied into their connection. Instead of dragging them down, it brought them closer together. Watching them find a way to heal side by side while going full throttle on their serial killer revenge plan was wild, but it made sense for their characters. It gave the romance this extra layer of depth because it wasn’t just about passion. It was about survival, closure, and finally finding someone who understood them completely.

Their connection felt equal parts passion and chaos, but in a way that made total sense for who they are. The banter, the tension, the sparks flying, it all just clicked. This couple made me laugh, made me swoon, and honestly made me wish the book wouldn’t end. Out of the series so far, this one might just be my favorite.

⟣Tropes⟢
✅ Touch her and 💀
✅ 🖤 Morally Dark Grey MMC 🖤
✅ 🖤 Morally Dark Grey FMC 🖤
✅ Stabby/Badass Heroine
✅ Banter *chef’s kiss*
✅ Sassy FMC
✅ Obsessive/JP MMC
✅ Dirty Talk
✅ Dual POV’s (first person)
✅ No OW/OM drama
✅ FMC not Virgin
✅ Found Family
✅ Pierced 🍆
✅ He falls first
✅ Stalker
✅ Masked MMC
✅ Chase/Primal
✅ 🔪 Play
✅ 🩸Bløød Play
✅ MINE
✅ HEA



‼️‼️‼️Trigger Warning‼️‼️‼️
I don’t have any specific triggers and was okay reading it without any warnings, but always take care of your mental health before diving in, since this book definitely has triggers.

[Faith · Rating 3 out of 5]

She carved her name into his skin… after her tattoos her with his bite mark. They’re perfect for each other

[Maria Cornejo · Rating 3 out of 5]

3.5/5⭐️… NECESITABA llegar a esta historia, y de verdad fue una real sorpresa, al fin conocemos que fue de Trey y de verdad fue SHOCK!, se descubrieron cosas que no veía venir, pero también hubieron cosas que se quedaron muy flojas… ese final fue tipo: eh? eso fue todo??? 👀
Pd: me reservaré mi opinión con la escena del cuchillo… me pareció muy WTF!! 😂
Pd2: que es esa sinopsis del libro 4?? 🤣 denmelo!!

[Krystle]

I’m gonna preface this by saying—I’m a dark romance girlie through and through. I like them so dark it hurts.

Did I enjoy this book? Yes, absolutely. I liked the plot, the characters, and their development.

However, I’m genuinely disappointed by the lack of ethical communication around trigger warnings.

——

So, to protect my reader friends—here are my honest thoughts:

There was no trigger warning present, noted, or even acknowledged in the book or its description. Not even a simple, “This book contains dark content—please take care of your mental health” note. The only warning I found was when I went searching for it. I found an incomplete list in a Goodreads review by the author, and after Googling the author and digging through their website.

**That information should be easily accessible and clearly stated.

This felt careless. It gives the impression that the author doesn’t value the emotional well-being of their readers—especially those who may be harmed by unannounced content.

Even more concerning: once I did find the trigger list, it was incomplete or inaccurate. It left out several major warnings, including sexual assault of multiple children. While not described in graphic detail, it’s present enough to be upsetting and absolutely deserves its own warning. (Yes this should absolutely be its own warning in addition to grooming or SA).

Stay safe, my friends. Your mental health matters. 🖤

[Lays Bloch · Rating 5 out of 5]

This woman needs therapy and I’m here for it. I love her.

[klinta · Rating 3 out of 5]

i will never not be a whore for a woman on a revenge mission decapitating her abusers at a halloween haunted house.

[Louise · Rating 5 out of 5]

This book was absolutely feral….. and I loved every second of it..

This booooooooook! Damn. This book was everything. Every page HIT. Easily my favourite out of the three books so far, and not sure if this will be topped.

The way I love Trey & Juliet so much. They were absolutely unhinged AF, feral, and totally obsessed with eachother. I knew way before reading I would eat them up, the tropes were a bit of me and they lived up to them.

This book starts with an absolute BANG, and keeps hitting… the storyline was amazing, the plot twists were 🤯. Their story had so much depth, and emotion. This is easily one of my favourite reads of the year so far… loved it. Ploughed through the entire book in less than 24 hours as I simply couldn’t put it down.

The spice…. Was EXQUISITE. It had me giggling kicking my feet…. I was panting. Absolute 🔥🔥🔥🔥🔥

I love them so much. I’m going to miss them… I need more of them. 🥹

Get it on your TBR now.

Super easy 5 star.

[Bianca · Rating 5 out of 5]

Ugh by chapter 2 I was securely on team Trey. Idk how Harmony managed to turn me so quickly but even after everything Trey did I instantly understood his motivation for his crimes in if you dare.

I don’t know if this is my favorite of the series but it might be tied for first. These two are the most meant to be couple I have read about in a long time and I ate this up. If you read drown in you then you know about Juliet’s little fascination with Trey but since he was kicked off campus that’s all it can be, they will never meet. Until his father buys his way back into school and the hockey team and he’s once again a devil.

This is far more than just a kinky, smutty book, there’s plenty of that too but these two connect soul deep. They are connected more than they could ever imagine. There’s nobody else who gets them or who can please them. They are who the other has been looking for. The little demon to his devil.

If you feel like you can’t forgive Trey, I promise you can just try and give him a chance you will not regret it. I will be feral until the next book comes out. Thank you for a crazy binge read Harmony!

[Shelby • the_kindle_girlie · Rating 5 out of 5]

I received this as an ARC.

Okay to be fair Harmony can only right bangers sooooo.

The 3rd installment of the Diamond Devils was so good!!! I thought Drown in You was going to be my fav, but Devil You Know came out swinging! Psycho stalking psycho!! I was so skeptical on Trey being the MMC. IYKYK. I hated him in book one, but absolutely fell for him in his book. Juliet… she was a wonderful FMC. She was fierce and took no shit from anyone. Their souls really are meant to be. This book was definitely darker than the first 2, but it might just be my favorite.

Trey Lamont is back. Everyone remembers what he did, but Juliet can’t help but be drawn to him . Her darkness calls to his darkness. After both of them escape tragic pasts they find the light within each other. This time they won’t be alone as their pasts come back to haunt them.

[Briana smith · Rating 5 out of 5]

5 FREAKING ⭐️
4.5🌶
At this point, this author is one of my favorites. I have read all her books and when I say...EVERY. BOOK. SLAPS. Hard. This was deliciously darn and depraved.  BOTH the characters are the epitome of RED FLAG. But baby wave that flag in front of my face all you want , I'm going to close my eyes 🥰
We got:
-obsessed stalker masked mmc? ✔️
-unhinged badass fmc? ✔️
-hidden identity? ✔️
-pierced, tattooed and branded fmc & mmc✔️
- revenge on past trauma ✔️

Also hit the trigger warnings spot ON. And the way she just had them both switch back and forth with it?! Who's hotter? I don't have an answer sorry. 😀😀😀 just think of all the triggers, they are in here😤
I need more, I'm begging you🧎🏼‍♀️

Bookstagram- romance with.bri

[Ceacea · Rating 4 out of 5]

Genre: Dark Contemporary Romance (Hockey)
⭐️ 4/5
🌶 4/5
🧠 2/10
Cliffhanger: 1/10 (Setup for book 4)
Noteworthy: Book 3 of a completed 4 book Interconnected standalone series. Dual first-person POV. Content warnings provided. Available on KU.

And the darkness meter came roaring back to the top in this one. Trey and Juliet deliver the unhinged couple you never knew you needed in your life. Two traumatized souls bound together by abuse and haunting pasts and a trickle of fate. The spice is really dark in this one so be sure to check the triggers. The revenge arc gives this book an almost thriller feel to it. If you liked book 1 you will love this one! And don't worry about not liking Trey because he will win you over!

[Megan Moser · Rating 5 out of 5]

Harmony brought it ALL in this book! 😍 It was everything I wanted and more. I love it when an author says we have an unhinged MMC and then ACTUALLY makes him unhinged. Trey was psycho in all the best ways but we also were able to see sides to him that I truly never saw possible.

His FMC was a spitfire and I loved everything about her. She was feisty, strong, and the perfect match to Trey. I knew she was going to be a wild ride from the last book but I never could have seen this version of her coming.

From the very first chapter I was so sucked in. I was walking around with that kindle in my hands everywhere because I needed to know what happened next. Their dynamic was probably one of my favorites I’ve read in awhile and I’ve read some really great books, but because Harmony put it all out there it just brought these characters to a whole other playing field.

I’m obsessed with this book! Be sure to check your triggers (but if you are like me and love all the triggers you will love this book too!)

[Meghan · Rating 5 out of 5]

We have touch her and Die, blood and knife play, primal, con non con. and it's so disturbingly well.🤭

🙌 the story I've been waiting for..bad guy Trey has his story to tell and I was here for it. Him and Juliet really were the perfect match. They matched each other's energy equally.

Juliette is obsessed with Trey when he returns to school. Wanting to learn about his crazy ass, and why he did what he did to Wes and Violet.. but while she is obsessed with him, but doesn't want him to touch her with a 10 ft pole. Trey is into her...

They're electric! a bomb waiting to detonate when they both are after the people that hurt them. I can handle a lot but what Juliet described her and another young lady going through made me sick to my stomach... and I had an inkling there was more to her and Trey.

Trey is also a survivor , not just from living under his fathers thumb, who is the absolute worse. I was rooting for his downfall from the prologue.

Thank you Harmony for the ARC, such a great redemption for Trey and I love him with Juliet.

[Shannon M. · Rating 5 out of 5]

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The Important Highlights
This is the third book in the Diamond Devil series which is dark romance meets hockey romance. These are plot driven, high intensity, dark romance books with heavy smut. These are interconnected standalones with first person, dual POV.

Content Warnings: sexual content, sexual assault, death, child abuse, trafficking, torture, and child death

My Unhinged and Messy Thoughts
Harmony West is the QUEEN of dark x hockey romance, in my opinion. I have been excited for this story since book 1, because I knew these two characters would be insanely unhinged. There is a lot of heavy content and this might not be for everyone. It is VERY dark.

In Conclusion
I will absolutely be reading the next book, the last one of the series! I will be sad when they are over though!

[Jessica · Rating 4 out of 5]

Book 3 in this series, and I hated Trey so much previously but he did redeem himself. Was this book unhinged absolutely, but these together was just wild.

I don't feel like I can adequately put into words what happened without giving spoilers. so I'll just say if you like unhinged dark hockey romance read this series but start at book 1.

Trey is the devil to Juliet's demon
Trey is Romeo to Juliet
They are prefectly unhinged together

[Savannah · Rating 4 out of 5]

Little demon

I forgot I pre-ordered this and the little happy dance I did once I saw it in my library ... well we won't go there. I loved this book. I think it might of been my favorite of the series.

[Moni · Rating 4 out of 5]

To było krótkie, szybkie i przyjemne. Nie wiem czy nie za krótkie. Absurdalność niektórych scen, może zaskoczyć, choć po opisie książki i lekkim wyprowadzeniu bohaterów w 2 części serii, można się tego spodziewać. Pozostaje czekać na losy pozostałych bohaterów.

[Alysha · Rating 4 out of 5]

“You should be locked up in an asylum somewhere,” I snap as I peel my dress off. He grins as he watches me strip. “Our future retirement home.”

What to expect:

* Unhinged psycho
* Black cat FMC
* Biker MMC
* Mutual stalking
* Possessive hero
* Dual POV

[Trista Williams · Rating 5 out of 5]

Ate that shit UP! It was dark and unhinged in the best way I loved their relationship