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Retrogression Keeper #1

The Lone Keeper: An OP MC Fantasy Isekai Adventure

What happens when a new Keeper recruit inadvertently eliminates not only the other recruits, but all of the teachers, as well?

At first, when Bax suddenly found himself transported from Earth to an organization of powerful, universe-spanning races, he was thoroughly confused. After he learned that his world was being forcefully inducted into something called the Retrogression System, which would introduce monsters to the Earth while eliminating all of the technology of the Humans living there, he understandably panicked.

Unfortunately, there was nothing that Bax or the Keeper Recruit program that he suddenly found himself being enrolled in could do about it. Instead, he was told that he had to learn how to be a Keeper, which was a powerful protector of the worlds included in the System in which the Earth was now a part. More than that, he was to become a Keeper Guide, a teacher of sorts for future Human Keepers once the Retrogression cycle began anew.

The only problem was that he had been transported from Earth while he was in the early stages of the flu he’d contracted from a co-worker. Bax’s experience being ravaged by the virus was unpleasant, to say the least, but he eventually recovered with enough rest. However, when he finally emerged from his room, ready to really start his learning as a Keeper Guide, he quickly discovered that the rest of the Cooperative seemed to be abandoned.

Now, what is a Keeper Guide recruit to do when there’s no one left to teach him?

This story contains an overpowered main character, LitRPG progression mechanics and stats, and isekai/portal fantasy elements. Contains no sexual content or harems.

359 pages, Kindle Edition

Published June 25, 2025

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About the author

Jonathan Brooks

94 books519 followers
Librarian Note: There is more than one author in the Goodreads database with this name.

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Community Reviews

5 stars
407 (57%)
4 stars
182 (25%)
3 stars
84 (11%)
2 stars
19 (2%)
1 star
13 (1%)
Displaying 1 - 30 of 38 reviews
Profile Image for David Campbell.
320 reviews4 followers
June 26, 2025
It's fine? The story isn't bad, and there aren't any glaring mistakes that I caught, but it doesn't rise much above that.

The MC is rather bland, and the only thing I can remember about him is that he doesn't like to be called by his full first name.

If you've like other stories by this author, this is another one. If not, I don't think I'd recommend this one unless you're out of other option. Again, it's not bad, but not much more than OK.

If you've read any of the authors recent works, you can probably guess the ending as its the same as every other book - every character from the story other than the MC is dumped to the side and the MC must leave the area and go somewhere new. I can't even call that a spoiler. it's like the authors calling card. I was going to go with 3 stars, but coming up with a new way to justify the lone wolf MC deserves less stars, not more.
162 reviews
July 8, 2025
It's not exactly bad, but not interesting, either.

Bax, the protagonist, gets boosted to be ridiculously strong, fast, and durable. He doesn't have any real skills or abilities, he's just at superhero levels of strength. He fights a lot of monsters, none of which are really any threat to him, since he's just so much stronger, and nigh-invulnerable. He generally dispatches high-level Kaijus by punching them really, really hard once or twice.

This is not interesting to read about.

He's also a bit of a bully when angry, though thankfully this only surfaces a couple of times.

No other characters are really developed. Quite a few of them appear for just a few pages, and then vanish from the book forever.

There are echoes here of Brooks's "Healer" books, which also features a character who is much more powerful than anyone else, in that when Bax does join a small party of adventurers, he generally does all the work while they just tag along, getting experience points just for being near him while he destroys every monster in a dungeon by himself.

This is somewhat inevitable because of the power disparity, but again, it doesn't make for interesting reading.
405 reviews
July 27, 2025
Idiot MC

Wow, why do authors create such idiot MCs. They seem to believe that hiding their identity or abilities is a cool thing to do when all it causes are problems, issues and misunderstandings that are so frustrating for the reader they want to stop reading. It may seem like a great literary tool, but it isn't. It only created stupid plot devices that require dues ex to be used in order to move the character along in the story. It also makes the MC a mentally weak, selfish loner who has little concern for anyone but themselves while knowing full well he could solve most of the books problems if he just spoke up.
Profile Image for Andy Murphy.
379 reviews1 follower
October 3, 2025
The Lone Keeper

When Bax found himself teleported out of his office and into a tower full of aliens, he didn’t know how to react. He was then told that Earth had just been inducted into the Retrogression System. This is the best way that the people of the universe have found to protect themselves from the monsters and the dungeons and towers that spawn them. Bax is to be humanity’s first ever human Keeper. He will learn the system this cycle, get stronger, then be able to help humanity. Unfortunately, Bax was coming down with the flu when he was teleported. After a horrible week in bed, Bax is feeling better and leaves his room to catch up on his studies and finds himself alone in the tower.

This was a great way to start an over powered character litrpg! Bax is an interesting character and did struggle to learn to use his new powers. One thing that I’m glad about is that he shows no interest in being an unstoppable solo killing machine and he is pushed to find a group. Despite the cover, Bax maintains his human shape. Miles Meili did a great job with the narration.

Content Warning: none
Profile Image for Aaron Eichler.
932 reviews
October 4, 2025
I love that Bax got stronger, but I understand that he has a lot of guilt on how he got there. There is no changing the past and just do better in the future. I was saddened that because I his sickness that Earth and thousands of other worlds as gone and only one is left. The best part for me was the pick of his first class, you can’t beat time. I am sure Bax in relieved that his secret is out so he can have influence without hiding. I am excited about this series.
132 reviews
August 24, 2025
reads like a YA novel

Not bad, but the overall story pace is uneven, and the quality of engagement is wildly different is various parts of the book.

Overall I probably won’t read the equal as it just fit not have “it” to make the reading experience as fun as it needs to be.


Quality of the formatting, Word choice, sentence structure and vocabulary was all good.
Story pacing could have used tightening tip.

If you’re a young teen, maybe read. For anyone else, pass.
Profile Image for Vader.
3,949 reviews35 followers
September 9, 2025
5 star - Perfect
4 star - i would recommend
3 star - good
2 star - struggled to complete
1 star - could not finish
Profile Image for Gandalfus-The-Colorful.
156 reviews
June 21, 2026
With only very few errors or logical inconsistencies, Jonathan created a masterpiece of modern Isekai Fantasy. For me, this is on-par with early "The Perfect Run" and early "The Stubborn Skill-Grinder in a Timeloop". (Though they had "no" errors and were logically more stable, as far as I remember.)

Just a thing that comes to mind: At the end, he just left without cleaning up the area around the town within a couple kilometers, despite knowing that monsters are only registered by the system if a sapient is perceiving it, therefore effectively being in stealth until they attack. Meaning, there could've been 10 level 100 Monsters in the forests around the town, 5 in the river and 3 flying close over the treetops - for all he knew.
This can of course be fixed "in post" ("post" being my mind while reading), but it would have been better to read it in a short sentence.
Also no programmer would limit an integer value to a max of 999 in a GUI if it can be higher and most of all not in the backend/calculations. Usually the only limit that isn't set by the programmer himself is are set by the available bits. For modern computers that is usually 64 bit, which can create one of the following limits for integers: If negative values are allowed -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807, and if not 0 to 18,446,744,073,709,551,615. Though there can be lower limits, like 8-, 16- or 32 bit. 8 bit would limit to 255, 16 to 65,535 and 32 to 4,294,967,295. So, as you can see, a limit of 999 makes no sense. A hyper advanced magitech server might not work that way, but even we lowly, weak humans are able to count higher than 999. :)

There were also more, as I said. Small things someone said or that happened. But I didn't make a list. I'm not your editor. :P
You still get 5 stars because this book is great and took effort and work to write. The idea is great too.
Profile Image for Fat Frog.
359 reviews
November 1, 2025
The MC is hard to take. He's an annoying, loner, loser who keeps trying to hide his identity and power for no reason. His internal dialogue is sooo boring. Way too many details about stuff that the reader just doesn't care about. Never does the MC run into any real struggles, he's invincible most of the book, except for when he gets hit by a mind attack... why don't enemies have mind attacks? Why only one random guard in town?

All Humans are somehow weak losers who just want to farm and fish????? What? Since when? It makes no sense. They all have the quick learner trait, which is very good.

I read the whole book, and would have given it 2 stars... but the last chapter made this 1 star for me. The system is just like "I'm gonna give everyone so much power, out of nowhere"... What is this trash? The whining of all the characters is so offputting. EVERYONE IS A BUNCH OF WHINING ANNOYING BITCHES. And all of the CONSTANT BLAME GAME. Everyone senselessly blaming everyone for everything.
Profile Image for Jonathan.
701 reviews
May 8, 2026
fun

Earth gets inducted into the System and the MC is the one chosen to become a trainer for future protectors of humanity. Humanity just has to survive without protectors for the first Cycle.
While in training a disaster hits and all the protectors both trainers and trainees die leaving the MC as the sole survivor. He is placed in stasis by the System until he can find a party, but when energy gets low he gets kicked out into the world.
As the protectors are seen as traitors for abandoning the world, he hides his identity and finds a party. He starts power leveling them. The city gets attacked by a super high leveled monster and he learns that he can’t stay in one spot for too long or the monsters start to rise towards his level. Book ends

A fun listen. Interesting world. Great pacing. Awesome narrator. All in all a wonderful read. Please enjoy
Profile Image for Travis.
3,219 reviews55 followers
August 31, 2026
The Lone Keeper is the first book in this series, and it's an interesting one. The main character (through no fault of his own) winds up being the only keeper left, and is basically kicked out of the training hall, due to lack of power to continue housing him. The adventures that follow are rather amusing, and rather tragic as well, but this world keeper isn't going to let anything get in his way of actually doing his job, even if the system is hosed. It leads to some awkward situations, and humans being treated as second class citizens, though that gets fixed in the end. Good story here, and I intend to read more in the series.
90 reviews
July 2, 2025
As usual, Jonathan Brooks delivers a story I had a hard time putting down.
Whereas I don't really like it when a character is over the top strong in LitRPG, it is how they get it, their personality, and what they do with it that matters. To be honest, how they got to be super strong has a giant hole I won't give away, though I guessed what was going to happen by page 2. HOWEVER, if you accept the starting premise and just go with it, it all makes sense from then on. And that's good story writing. There is character development, excitement, will it all work out, etc. It's very well written and it kept me wanting to read on to find out what happens next. And THAT is my biggest rating criteria.
1,287 reviews18 followers
June 27, 2025
worth five stars, with a few issues, but nothing is ever perfect

Really great story, read it from beginning to end in one day. Like most beginning stories, slow to start, but picks up later on in the book. The only thing I did not like was the character being stuck at level two and that he cannot stay in one place but has to do the Incredible Hulk routine going from place to place. in my head, I hear the lonely man theme. hopefully the author will change that particular point in the story if not, the fact that the characters is stuck at level two. besides that the book was very enjoyable, really can’t complain. Liked it very much. Will read the next one.
Profile Image for ConciseAlan.
294 reviews4 followers
January 20, 2026
This author's books have something in common, and it's not a good thing. All his MCs are pathological liars. At least they get caught in their lies, sometimes. The lying in this one doesn't start until chapter 18, and I haven't decided whether to DNF it, as I've done with the completed eight-book series, Magical Fusion. I made it to book 2 in that one as the YA flavor was just too strong. The writing is decent and the editing is pretty good, but could use one more pass. (Don't authors use grammerly or something like that?) Anyway, it's a fun read until the lying starts. It was headed to four stars, maybe 3.5, before that.
12 reviews
January 17, 2026
Good book but a bit rushed at end

I liked this book. There were many times when I did not know where the author was going to go which is nice in books like this. I liked the unique twist that was given to someone that is overpowered. I am just a bit disappointed that the book was really rushed at the end. If the author had added 3 or 4 more chapters and slowed down the ending he could have set up the MC a bit better. Even with the weird rushed ending I am looking forward to the next book.
Profile Image for Kelley.
715 reviews22 followers
July 20, 2025
bleak beginning but good book

This book’s beginning is so bleak I almost stopped reading it. I’m glad I did keep reading it. Over all I think it was a well written book that was completely different than I was expecting. The main character acts like a young adult and a lot of his decisions only make sense through that lens. I’m eagerly waiting for the next book in the series.
42 reviews
October 2, 2025
**I Couldn't Stop** I love the complex narrative of the underlining story. It's not just another OP MC that is just OP for seeming no reason. I love how Jonathan brought his own personal "what if" into the making of the story. I can't wait to see how this series progresses, if it's anything like Jonathan's other works, it is going to be Fantastic!!
Will Keeper Bax save all of civilization? or will he be the reason it is destroyed? I really hope we get to find out.
140 reviews
November 26, 2025
Not bad started really interestingly to oh my what's he going to do now but then has a lot if info dumps so very prepared all lol, anyway one thing really got on my nerves was constant group and team work thing needed and forcing on mc I love solo adventures with just occasionally grouping up so found this very frustrating to often just wanted give up on whole book I am hoping mc can do more alone or I will give up sorry as just wouldn't be for me.
Profile Image for Ken.
530 reviews11 followers
June 24, 2026
It started a bit slow, but then picked up a nice pace. LitRPG in general is very hit or miss for me, with there being more misses than hits. Overpowered main characters even more so. But this one was a hit. The OP aspect has an interesting background and it progresses nicely from there. The MC remains a bit bland, but that's a mild complaint. I did enjoy it and moved on to the next book immediately.
Profile Image for Janet.
29 reviews
June 29, 2025
Good first book

Unusual idea for a book of this type. Usually when this happens to a person they are immediately healed by magic. I could see maybe all the level ones being affected but not the teachers and healers. It is kinda sad that everyone would die. Also you would think that system would be smart enough to fix things.
Profile Image for SVETLANA.
434 reviews67 followers
July 8, 2025
As always, for Jonathan Brooks' books, this one is good.

This time, it is a Portal's world idea at the base and beginning of the book, and the way the main character acquires extraordinary power is interesting and unusual.

I started it 4 stars only because of MC's indecision to let people know about him. But let's wait for the next book and see what's going to happen in the future.

Profile Image for Jerome.
36 reviews
July 14, 2025
Far too bleak

The opening events of this novel are so catastrophically cruel and bleak that it turned me off immediately. Though it should be expected with this author's other works, the consistent eradication of the majority of life just to facilitate OP characters is not worth reading his works.
Profile Image for Michael Ballinger.
91 reviews1 follower
May 31, 2026
A Great Start!!

Jonathan Brooks does a fantastic job at writing these entertaining books and is on a roll with this one! The crazy premise of being isekaid while sick and horribly ending all the keepers in another world who have no immunity!? That’s insane, but here for it! Overall, the start was a little slow, but the build up until the ending was amazing!
42 reviews
June 27, 2025
Grew new series

I've been reading this authors other series so getting this book was a no-brainer. It goes hand in hand with his other series The Unexpected Healer so I expect similar good things out of this series too. When is book two coming out????????
Profile Image for James Riley.
1,400 reviews20 followers
August 6, 2025
Really good

This book was a ride. I say that in the best possible way. It has a great MC, awesome plot, and lots of heart. Do yourself a favor and pick this book up.

Highly recommended.
404 reviews5 followers
August 31, 2025
As always a riveting read

I always love Jonathan Brooks books. They pull you in and it’s hard to put them down. The characters are always so rich, which makes the traumatic parts really hard sometimes. But always satisfying in the end.
78 reviews2 followers
September 5, 2025
finally an OP character with consequences

Enjoyed the premise and world building even if all the sneezing and coughing triggered me as I am prone to sickness. It was a fun read. I look forward to more.
Profile Image for Danny Moody.
1,550 reviews15 followers
October 8, 2025
With the name retrogression in the title, I was hoping for some time regression but no luck. We do get an accidentally overpowered MC. Despite his strength, he has to function in a unique mixed species world. This was a fun read and I look forward to more.
87 reviews
March 21, 2026
Very different!

If you've ever wondered what would happen if someone were Isekai'd while sick? Well, now you know! It's certainly not exactly what I expected. Check out this OP MC Isekai story!
Profile Image for Nathan.
1,288 reviews4 followers
May 1, 2026
friendship is the true treasure

Unique System of retrogression (every cycle, all levels are reset for everyone, like starting a new Pokémon game), bland protagonist uniquely suited to being ripped from Earth (orphan).
Displaying 1 - 30 of 38 reviews