I'm a librarian who loves anime, manga, and reading a wide variety of genres.
When people die, their souls move on via White Gates. However, there are also such things as Black Gates, Gates that forcibly suck the souls out of living humans, causing mysterious suicides, murders, or massive disasters. People known as Mitedamashi find Black Gates and close them.
Senju is a Mitedamashi taking care of a young boy named Hijiri, the world's only surviving Gatekeeper. In theory, Gatekeepers are even more powerful than Mitedamashi, possessing the power to close all Gates and end death forever, but Hijiri can't even manage to close the smallest Black Gate. This bothers him, but what he doesn't realize is that having his full Gatekeeper powers could put him in the same situation that ultimately led to his father's death.
Although I tend to be drawn to short series (so much less daunting than the ones with volumes in the double digits), it's rare to find good ones. I didn't go into Black Gate expecting much, and for a while it looked it it was going to be an okay but mostly forgettable series. Unfortunately, then it started to become boring and confusing. I slogged through it, hoping that it would get better. It didn't.
The setup was pretty generic, but that would have been fine if the characters had stood out more and been more appealing. Unfortunately, Hijiri was annoying (he reminded me of Naruto at his brashest and loudest), and Senju was boring. The characters introduced later in the series weren't much better. Tsurugi was cheerfully dense, and the way Sumiyoshi wrote about his attachment to his deceased younger sister made their relationship look almost incestuous (Tsurugi's older sister kept telling him to move on and find a girlfriend). Michitate and Michizane's antagonistic relationship was mildly interesting, but they had to fight all the other characters for page-time. While I liked that the rift between them took time to be repaired, the stuff with Michitate's mother was dealt with way too quickly and easily.
Hijiri's father, Yoshitsuna, just confused me. The explanation given for the two wildly different ends of his personality spectrum didn't work for me. Well, it did at first, but then the ending happened. I had trouble believing that Yoshitsuna would have needed to have the exact same epiphany twice.
Then there were the things that just didn't make sense: Hijiri asking Michitate, who he hadn't known for very long, about Michizane's mother even though he knew it was a sore spot; that the truth about Michizane's mother could have been hidden for so long; the stupid reason Michizane hid the truth from Michitate. It didn't help that the series' pacing was weird and jerky. The first volume in the omnibus had Senju and Hijiri dealing with Gate-of-the-week style stories, until the flashback to Senju's past. The next volume had Hijiri meeting and teaming up with his Guardians in order to investigate Mitedamashi deaths. The final volume had magical battles and most of the characters doing things that kept the story moving along but that were out of character for them. The time jumps at the very end felt like the writing equivalent of a face plant.
I can't recommend this series. It was bland, poorly constructed, and sometimes confusing. Even the artwork could have been better.
For a while I thought this manga was going to end up with a 2-star rating. The badly executed ending bumped it down another half star.
(Original review, including read-alikes and watch-alikes, posted on A Library Girl's Familiar Diversions.)