Umbra
by Amber Toro
Reviewed by BroMantasy on August 24, 2025
Est. Reading Time: 10 min

Quick Info
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Author: Amber Toro
Series: Sentient Stars (Book 1)
Published: April 24, 2024
Rating:
ISBN-13: 9798990173903
Umbra by Amber Toro
At a Glance: A SciMantasy Space Opera
Umbra is best described as a space opera with a romantic sub-plot that is perfect for those who are hesitant to get into the sci-fi genre, but specifically the space opera sub-genre. It is accessible to newer readers who have been intimidated by the grand scale of some of these universes, but with all the elements that will feel familiar to seasons space opera vets, while adding in sentient AI powered bio space crafts that have their own personalities and bonds with their captains.
Umbra is set around 10,000 years after humanity left the “Earth that was” and became a civilization that mostly spends their time on space stations and space ships, with fewer living planet side, and humanity now consist of 12 tribes under the United Tribal Access(UTA).
The story switches between three different POVs seamlessly to give views from different perspectives of not just people from different tribes, but from all different walks of life. The 12 tribes work together and most of our views have some current or former involvement with the UTA Navy.
United Tribal Axis: 12 Distinct Cultures Post Earth
Umbra doesn’t disappoint when it comes to world building, especially in regards to the political maneuvering I’ve grown to expect from a space opera. The 12 tribes add some distinct elements, with each tribe excelling in one area or another, but the most poignant thing about them is their philosophical differences. From what we see in Umbra there is a large split between those who believe in individualism and those that are more of a collective for the good of the tribe mindset. This leads to a lot of politicking and scheming that directly effects the plot and shrouds a lot of what is happening in mystery to keep the story engaging.
The most unique thing about Toro’s world has to be the AI bio-ships, which are starships that are bonded to their captains from birth, they are sentient, have distinct personalities, and advanced hybrid construction. Their pilots have the ability to create a full link of their consciousness with their AI counterparts to perform advance manauvers during dog fights, and each ship feels just as human as their counterparts, their personalities are all different, they enjoy the company of other AI ships, and even meddle in the lives of their captains like you’d expect from a human best friend.
There are definitely aspects of the more science forward themes like quantum physics without info dumping onto the page or making you feel like you need a doctorate to understand what is happening in the scene. There is also a ton of talk around AI and code in general, but again fits the narrative without making you feel left out or that you need to know these things to understand what is happening.
Character Tension: Bonded Ships, Guarded Hearts
Toro has an incredible talent for writing characters that feel real, and that shines through in each POV, their voices are all unique, and their interactions never feel robotic, even when interacting with their bonded AI ships.
Skyla is our former UTA Navy pilot turned “archaeologist” which in the world of Umbra means she salvages forgotten tech in the outskirts of UTA controlled space. Skyla left the navy to seek adventure only to be sucked back in when her circumstances force her to face the responsibilities she desperately sought to escape when she finished her Naval service commitment.
Hinata is a Commander in the UTA Nave, who is banished to a research planet after failing to make admiral and becoming a disappointment to his tribe and their leader who also happens to be his mother. He’s a by the book hard ass with a chip on his shoulder, and has been plagued for years trying to figure out how he was passed up for the Admiral position after winning the final assessment.
Freyja is the direct counterpart to Hinata, who lost to him in the Admiral exam but was still given the position over him. Like Hinata she is daughter to the Empress who has overwhelming political pull, and expects Freyja to follow her orders without question, even when they directly conflict with her duties as an Admiral in the UTA Navy. She always has Kylian and Tristanher, her duo of elite “berserkers” with her.
The supporting characters are all very well done, including Pele, Skyla’s bio-ship, who is snarky, a bit of a romantic, and she really comes off the page when she meddles in Skyla’s love life.
Epic Scope: Slow Ramp Up
Toro’s prose was outstanding, very easy to read, and she absolutely shines during character moments, but like many series starters in the space opera genre, the beginning can feel a little slow to get going with introductions to new elements, technology, and characters.
While there is a good amount of information, it never feels like you’re reading a technical document of the world like some sci-fi books suffer from, Umbra delivers it’s world building in an organic way through character experiences, but the plot really starts to come together about 1/3 of the way through and that is when the book starts to really shine.
The action scenes are great, they perfectly balance the emotional stakes for the characters involved, with description of the battle scenes that feel like you’re watching an actual space battle unfold.
While the action scenes were great, the quieter moments where characters are sharing a drink, or discussing plot related research are where Toro shines. Her ability to write romantic tension was really enjoyable, and she knows just how to rip the rug out at the right moment to leave you feeling that frustration that you assume the characters are feeling in that moment. For all my fans of the “yearning” romance plot lines, Umbra won’t dissapoint.
Between the Sheets: Romance Conquers
Umbra has an incredible romantic sub-plot that is filled with yearning, near misses, and that satisfying moment of finally connecting, but does so without ever letting us peak into the bedroom earning it a 🌶️(1.0) spice rating.
Hinta and Skyla are the perfect example of opposites attract, the hard ass by the book Commander and the independent rule breaking “archeologist” don’t quite hit that true enemy to lovers trope, but it still has those vibes. The yearning, flirty banter, and tension between the two is perfect for anyone who enjoys a good slow-burn, and while there is an occasionally steamy make out session, we only get some implied sheet tumbling in this one.
Bro Reading Comfort: Space Opera With Stunning Cover Art
Umbra is a sci-fi space opera with nothing that would make you blush while sitting at the coffee shop enjoying an incredible pumpkin spice cold brew (it shows up earlier every year, and i’m not mad about it 🤷🏻♂️) earning this one a 😳(1.0) for public reading comfort.
The cover are for this book is incredible, I’m not joking when I say I literally bought a hard back because I need this as one of my cover out “display” books on the shelf. The story was great which certainly helps, but as a “judge a book by it’s cover” reader, this one is 👨🏻🍳💋.
Darkness Factor: Space Can Be A Little Dark
Toro certainly doesn’t shy away from the more uncomfortable things like emotional abuse and manipulation by family, but overall this doesn’t ever get too dark or gory earning this a 💀💀(2.0) on the darkness scale.
Hinata, Skyla, and Freyja all struggle with trauma from family manipulation and it’s effects on someones ability to trust, love, and figure out how to navigate life when dealing with that type of emotional struggle.
Feyja especially stands out here, when from a young age she was manipulated and forced by the Empress to do her bidding and any resistance was met with emotional abuse through pain to the ones Freyja cares about most.
Book Battlefield: SciMantasy Might Become a Thing
Much like Romantasy, I feel like the sci-fi genre could use a little more romance written into their stories. Umbra I feel like could be something that helps carve out this interesting niche in the genre, while at it’s core it certainly fits the space opera sub-genre, the romance adds so much to the deepening of the character development and it really enhanced the story for me.
Now if you’re someone who hasn’t read any sci-fi or space opera, I think this would be a great entry point, as I mentioned in the glance section, this book doesn’t over-do the science of the science fiction, and keeps the information flowing at a manageable pace for those who haven’t been exposed to the immensity that comes with building an entirely new universe.
For those seasoned in the trenches of grand space operas, or coming off the heels of something like the Sun Eater series or Red Rising then you might be left wanting a little more from the science pieces, but Umbra more than makes up for it in the area of character development and relationships.
Should You Bother?
For Character Driven Readers: Toro creates interesting characters, with distinct voices, unique backstories, and overall great dynamics
For Those Interested in Sci-Fi: Umbra is an incredible entry point, delivering all the science in an easily digest-able way, never making you feel like an advanced degree is required
For Space Opera Fans: I really did enjoy this book, I think it does a good job building a new universe, with the beginning of some good politics, and a super unique concept with the AI bonded bio-ships.
For Bonded Rider Fans: The AI bio-ships bonding to their pilots from birth does a great job at using this tried and true fantasy trope in a sci-fi world.
Final BroMantasy Verdict
Umbra was an incredible read, I’m a big space opera fan who absolutely loves series like Red Rising, where even though it’s not the focus, there is a good romance in the background. What Amber Toro has done here is take all the things I love about the space opera genre and enhance it with her incredible ability to write believable characters, and deep romantic relationships with the “will they or wont they” yearning i’d expect to find in a Romantasy, earning Umbra a 4.25/5.
This book really was great, and I think I’ve beat y’all over the head with how good Toro is at characters, but what I didn’t go deep on was the other standout of this book, and that was taking the bonded rider trope from fantasy books and integrate it into a space opera. The bond between Pele and Skyla had that same feeling as Tairn, Andarna, and Violet in Fourth Wing. Pele was sarcastic, overbearing, and meddlesome making the ship feel like she was another full developed character just as important as any of the main POVs.
While it’s a bit of a slow start, when this baby ramps up, it becomes a constant page turner where you don’t want to put it down. Once Umbra gets out of the building stage and hits it’s stride Toro begins to really shine, not just in her character work, but her ability to write battle sequences feel like pure cinema, full of action, vivid detail, and threats that feel palpable.
Umbra is the first book in a series I will certainly be continuing, and one I will recommend to anyone looking to get into the space opera genre that may be intimidated otherwise, Toro has made this niche genre a little more accessible, but also has possibly stumbled into something I didn’t know I was looking for, SciMantasy.
Frequently Asked Questions
Is this book part of a series?
Yes, this is book 1 in the Sentient Stars series.
How spicy is the romance?
We rate the spice level at 🌶️ (1/5). Yearning and tension with implied intimacy but no explicit content
How uncomfortable is it to read in public?
We rate the public reading discomfort level at 😳 (1/5). Space opera with stunning cover art perfect for coffee shop reading
How dark are the themes in this book?
We rate the darkness level at 💀💀 (2/5). Family manipulation and emotional abuse themes without excessive gore
What age group is this book for?
This book is generally recommended for adult readers due to its mature themes. We recommend checking specific content warnings if you are sensitive to certain topics.