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Untamed Aggression (Bikers of Mayhem Book 4)

Matthew Dante
4.6 / 5.0
Published: 2026

Description

Marcus is the hardened, no-nonsense leader of the Shadow Vipers, a man whose life is a constant cycle of wrangling his chaotic biker brothers and keeping his crew out of the morgue. He values control, silence, and order—everything that Gavin, his latest forced responsibility, is determined to ruin. After a disastrous run-in with a serial killer, Gavin needs a protector, and Marcus is the only man tough enough to keep the influencer alive. Gavin is a twenty-four-year-old romantic who possesses the unfortunate talent of choosing the absolute worst men to date—including the man currently trying to end his life. Now, he’s hidden away by a grumpy, imposing biker who finds his constant chatter grating and his presence a massive headache. Yet, beneath Marcus’s scowl and Gavin’s high-energy exterior, a dangerous attraction begins to simmer. As the threat of the Valentine Killer looms, these two polar opposites must navigate a high-stakes world of violence and loyalty. Can the stoic biker find room in his rigid life for a chaotic force like Gavin, or will their combustible chemistry destroy them before the killer ever gets the chance? This is a thrilling ride through the gritty, heart-racing world of the Shadow Vipers.

Customer Reviews

Top 5 from Amazon
L
LC
May 10, 2026

Untamed Aggression. book 4

I love this series!! The Shadow Vipers seem like big bad dudes, but they are really softies under all those tats. This has a story I’ve been looking forward to even if I wasn’t sure it would happen. Marcus had always been attracted to women before and it wasn’t until he met Gavin that he realized his sexuality might not be as hardwired as he thought. When I read the part where Marcus thought that he didn’t have time for a relationship, I was sad. Everybody deserves to be loved even grumpy bikers who hide their marshmallow hearts. Matthew Dante writes these larger than life characters that I can’t help but fall in love with. The bikers are a family unit and they protect each other at all times. Of course, they were going to help Gavin. They have their own code. The ride through this story is so good. It was so hard to put it down. These characters make me happy. The best part? At the end of the Acknowledgements, there is note about their story never being over. 😊
M
Macbandit
May 8, 2026

Odd pair

Matthew Dante Untamed Aggression I have enjoyed all the books in this series but this one just gave me the can’t set it aside reading. Marcus has had his share of issues from the time he was a young kid but always being the parent seems to be his way of life. It sure directs his life being head of the Shadow Vipers bike club. When he is asked by the sheriff to protect Gavin he is thrown out of his comfort zone. Marcus gave me more than one lol moment. Gavin, looking for more than the no attached lifestyle, goes on a date with who he believes is a doctor. This date does not turn out at all what he expects. He ends up needing protection from a serial killer and finds himself faced with a biker who doesn’t know what to do with him. Gavin from the beginning is mouthy, flirty and a general disruption to Marcus’s life. To me this is a fun, comfortable romance. I started it and found it easy to read and hard to put down. I can’t wait to see the next book in the series.
D
Dr. Kai
May 8, 2026

Disappointed

I have to say, I want into this having high hopes but sadly fell flat. I was not onboard for this story. I found it boring to be honest. First I found Gavin to be completely annoying and acts more like a kid than an adult, he was very unlikable. Marcus I did find somewhat interesting and likeable, but the pairing just did not work for me. There was no growth or chemistry between the characters. I really wish this could have been better and OMG I hated the whole influencer by day and romantic with bad taste in men joke just was played out. The instant love was very over done. The action was good for the most part. I just hate that is felt more like a teenage brat than a adult for Gavin.
L
Lyndsay TC
May 8, 2026

Marcus!

The head of the Shadow Vipers, Marcus got unexpectedly waylaid by social media influencer Gavin while protecting him from a serial killer. Marcus never thought he would fall for anyone much less a man but the heart knows no bounds and his heart wanted Gavin whether Marcus liked it or not. Action, found family, shenanigans, spice and love make up this fun book.
D
Danielle
May 11, 2026
Verified Purchase

LOVED

This is one of my favorite authors. I always look forward to a new release. I have been enjoying this series and have been looking forward to Marcus's book. This was fantastic. It had it all. A fantastic storyline filled with non stop action, found family, a beautiful love story, and the villain upon all villains. This was the story I have been waiting for and I was not disappointed. I recommend reading this book and this series.