A reaction channel I watch recently started Yu Yu Hakusho, and since I own all the manga volumes I started flipping through them to compare with the anime. That is actually a pretty interesting topic in itself as anime cuts a lot of early content from before the series actually settled on what it was going to be, and changes or adds other things to make the early stuff more consistent with the rest of the series. But I also started skimming ahead and I remember not really liking or getting the ending back in the day. On rereading the last arc and kind of liking it, I had two realizations. One is that I've gotten old. The other is that I think the reason for my opinion then and now is that Yu Yu Hakusho did something that may be almost unique for a shounen series. It grew up.
That may seem like a strange assertion given how many shounen action series are fundamentally coming of age stories, or how DBZ is DragonBall but now everyone is grown up. But it seems to me that in the former case when the main characters finally take that last step out of adolescence, is when the series ends. Cut to credits, everyone lives happily ever after. FMA seems to me like a good example of this. DBZ on the other hand... look the fact is Goku just remains a manchild. Like, that is over half the joke most of the time. Krillin has what is actually a pretty complete arc, but that arc also kind of basically sidelines him for big chunks? And I haven't really paid any attention to Boruto but I would assume that it is explicitly at least in principle moving the focus to a new adolescent protagonist.
But Yu Yu Hakusho I think goes over the top, at some possibly unidentifiable moment, and then just keeps going for another dozen or so chapters. Which I think probably contributes to some the weird pacing and feel of the last bit. After the big climax of the Chapter Black arc, the entire last arc ends up with a series of anticlimaxes and arguably a complete collapse of the whole shounen formula. It's like the series isn't a shounen battle manga anymore, but rather a seinen series with the trappings of a battle manga. Everyone is settling down. Yusuke gets a job, Hiei gets a girlfriend, etc. Also kind of unusual for this kind of story instead of the fantastical element becoming lost or cut off forcing the protagonist to go back and stay in the mundane world, the fantastical just becomes part of the mundane. Yusuke I think in particular as the protagonist has become mature, both in terms of how he handles the problems in his life and his certainty in what he wants out of life, long before the final chapter.
And it basically has the Return of the King problem of hitting what you would expect to be an ending, and then it just keeps going and has another ending, and then another, and so on. It dies with a whimper, not a bang. Which I guess is to say that the ending of Yu Yu Hakusho feels as rough and unplanned as the beginning did.
The end result is strange and frankly awkward from a storytelling point of view but also fascinating both in comparing where the series began to where it ended, and a comparison to other manga.