

I try to keep these short, spoiler free, and easy to digest.
I'll start by listing everything you need to know, and if you are still interested, you can read the rest of the review.
Also, this is a review of the entire series, not just this first part.
Personally, I like Umineku. I like it a lot.
It's a fantasy murder mystery that tries to let both "facts-n-logic" and "lol-it's-magic-don't-think-about-it" coexist, and for the most part, it succeeds.
Also, unlike most mysteries, it actually sets up the clues for resolving the mystery over a long time, giving the reader many chances to realize the truth themselves, instead of just pointing out that the one tiny detail you skimmed over was the key to everything.
Another point in favor of Umineko's mystery is that when something seems to be incosistent, it is later on acknowledged by the characters themselves and used as a story element, which is a very unique writing style. It's like when the teacher makes a mistake, and then when asked about it they say "I was just testing to see if you would notice". In the end, it all connects together and makes sense.
For the most part, the manga revolves around the mechanics of a unique game - a debate where the judgement is objective, where one player knows all the true facts but has to convince the other player in the truth of a specified fake reality. And at the same time, the other player, who has close to no knowledge on the actual reality, must use logic to disprove every one of the fake facts and find a plausible truth to win the game. In this case, the player holding the real facts must prove that magic was the murder tool, and the other player must disprove it and find a murder method possible for normal humans.
The biggest strength of this unique game is that, for the most part, the "power" escalation is actually an escalation in the difficulty of the mystery. Thanks to the challanges being intellectual, there's no powercreep, and the growth of the main character feels earned - because you, the reader, are undergoing the same growth, learning and applying your newly acquired knowledge in the same way as the main character.
If you enjoy debates and rule lawyering, you will likely enjoy the hell out of this.
The characters are all fleshed out, and most of them are not tropes.
Due to the nature of the debate game, every character is a possible suspect, and therefore every character has darkness that could act as a motive for murder.
In that sense, every character in the series is edgey and a drama queen to some degree. I usually don't like this sort of stuff, but with the in-universe excuse of "You're lying, this is fake, that character would never do that", suddenly this sort of writing becomes a great tool for painting the same character in multiple, contrasting colors that force you to doubt new information and previous knowledge. Maybe what you saw until now was the fake truth?
The art is pretty good too.
Consistently detailed backgrounds, great character designs, magnificent facial expressions, and very nice paneling.
However, this series isn't without it's flaws.
The story is goddamn LONG. It's full-length is equivalent to a long running shounen. And don't go in hoping to read just the first part, it isn't like Jojo's Bizzare Adventure where every part is almost a full-fledged-story. The story gets twisted at the end of every episode, with the following episode continuing where the previous left off.
Another minus of the story is that, for the sake of setting up future plot twists, sometimes it just drags on or gets too confusing to keep up.
Also, sometimes absoloutley normal characters turn out to be chuck norris levels of power. It's like a shitty fan fiction, and while it is important for the plot and makes sense in the rules of the debate game, sometimes it is a bit too much for my suspension of disbelief.
About the ending (spoiler free).
Endings are important. And for some reason, most mangaka can't into satisfying endings.
Umineku did a pretty great job at giving proper closure to all characters, and it didn't do it in one go too, so you have a proper breather between each character's departing to actually feel the impact.
Pretty great for those who enjoy debating all day, and can handle very long mysteries.
85/100
Minus points mostly for the main characters being a bit incosistent in their behaviour.
If you decided to read the manga, here's some advice:

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