Is this my least favourite Rumiko Takahashi major series so far? Maybe. I'm not sure. That's excluding short series like Mermaid Saga, by the way. It's still Rumiko Takahashi, of course, and I'm happy to keep watching, but so far I don't feel that the show's either serious (e.g. Inu-Yasha, Maison Ikkoku) or full-bore comedic (Urusei Yatsura, Ranma). Yes, I'm aware that Maison Ikkoku's both. Kyoukai no Rinner, though, is drifting somewhere in between.
I should emphasise that I still like it, though. I'll be sounding negative for a chunk of this review, but it's a good, entertaining anime. It's amusing and can be laugh-out-loud funny. The cast is reasonable and it's got one standout character (Sabato Rokudo). By all means watch it. That said...
Theoretically it's got a horrific premise, but the show's not taking anything too seriously and is instead more about lighthearted misadventures. Rinne is a half-shinigami, i.e. Grim Reaper. He harvests the dead and helps lost spirits release any regrets that are holding them on Earth. He's conscientious. He's a nice shinigami. Not everyone's so benevolent, but crucially this show's view of death is a cuddly, Buddhist one where the deceased just get on the Wheel of Reincarnation for another go. It's never scary or disturbing. It's family-friendly. You could show it to little children... and yet some of Rinne's enemies are going further than you'd expect in such a pleasant-looking anime.
1. Rinne's father, Sabato Rokudo, is a scumbag whose company makes its profits by harvesting people before their time. In other words, he's organising mass murder. That's his business plan. The rest of the cast seems to see this as, at worst, a bit naughty. Admittedly this sort of makes sense in-universe, given the Buddhist reincarnation thing, but it might still be a bit of a "blink and rub your eyes" for the audience. That said, though, the Damashigami Company is just one of many, many reasons why we're looking at the biggest jerk in the rich pantheon of Appalling Rumiko Takahashi Fathers. (And you thought Ryuunosuke, Ranma and the Kuno siblings had it bad.)
2. Kain's future was ruined when his mother was swindled by Rokudo. He couldn't even afford to go to high school. Now he's boiling with hatred and bent on revenge, trying to force Rinne to repay the debts to which Rokudo fraudently made him a co-signatory. That might not sound too bad, but Kain works in the afterlife. He can sell Rinne's life force as loan collateral. He's trying to kill Rinne for the crimes of his father.
At root, though, it's basically about Rinne being dirt poor, Sakura being emotionless and their friends being a bit dim. Rinne has massive debts and no money. (Guess who's to blame.) He lives in an abandoned building, weeps tears of blood if forced to spend money and will freak out about small change. This can be, in fairness, quite funny.
Meanwhile Sakura is an ordinary girl who can see spirits and hangs out with Rinne a lot. Clearly they're the Main Couple, destined for each other as with Lum-Ataru, Godai-Kyouko, Ranma-Akane and Inuyasha-Kagome. However Rumiko Takahashi has a reputation for creating explosively short-tempered couples who can't stop arguing, with lots of richly deserved female-on-male violence. Here she's trying something new. Both Rinne and Sakura are calm, deadpan and apparently emotionless. They're sensible. They underreact to things, instead of overreacting. They certainly don't argue, although oddly this makes it harder to get through to Sakura when there's been a misunderstanding.
With Rinne, it's a mask. He's just stoic. There's a lot underneath those impassive non-reactions. With Sakura, though, she genuinely is like that. At its most extreme, you might wonder if there's something wrong with her. She never gets scared. Her idea of surprise is an "oh!" There's a lot I like about this, but unfortunately I also think Rinne-Sakura have turned out to be less entertaining than Rumiko Takahashi's other couples.
I've heard people call this show "cold". I don't quite agree, but I can see how someone might feel that way. (I'd also point at the show's fondness for jokes based on people being disinterested to the point of callousness. Personally I find them amusing, though.)
Rinne is quite funny. Sakura I like a lot, but she's not always as prominent in the stories as I'd like. (She can't fight and she doesn't have shinigami powers.) Beyond them, though, I'm not sure about the rest of the cast. Rokumon's fine, but he's basically just Rinne's sidekick. Tsubasa Jumonji fancies Sakura and is pleased with himself, but he's also a bit too vanilla to be memorable. I'd say the same of Ageha, but gender-switched and perhaps to a slightly lesser extent. She's stupider and she likes Rinne. We know she's doomed to fail. After that... well, Tamako's fine. Masato's fine. Overall this is a perfectly decent cast and normally I wouldn't have been complaining, but alas I can't help comparing them with Urusei Yatsura and Ranma 1/2.
There are two Rumiko Takahashi veterans in the voice cast. Sabato is Kappei Yamaguchi (Ranma Saotome, Inuyasha) and the minor role of Sakura's mother is taken by Fumi Hirano (Lum in Urusei Yatsura). She even has green hair and tiger-striped clothes.
By only being on TV for half the year, they've also solved the problem of anime filler episodes. Six-and-a-bit manga volumes got adapted this season (plus what I think is an original Christmas episode), although they skipped around a lot. Ep.23's taken from vol.14. However the manga's serialised in a weekly magazine, which is just over five new collected volumes a year. If the anime went back to adapt every single chapter, Takahashi could keep doing this series for another 22 years before the anime caught up with her.
I don't know. I'm probably overthinking it. It's still early days. 25 episodes is a flea-bite in Rumiko-land. There's going to be lots more Rinne and there's still room for the cast to grow and surprise me. I'd like more eccentricity and a few more Sakura-centric episodes, but then again Ranma 1/2 can get repetitive with all that martial arts and I actively dislike Urusei Yatsura's first fifty episodes. Kyoukai no Rinne struggles a little if marathoned, but you might struggle to do that with those other two shows too. Its format can feel a bit static, but we're nowhere near Ranma levels yet. The show's fine. I quite like it.
LATER UPDATE: I think I was wrong. I've slept on it and I think the memory cheats. A normal Rinne episode is probably as funny as a normal Ranma episode, but with less slapstick. Ranma has more memorable high points, but Ranma also had 143 episodes plus OVAs and films. I'll call it a tie so far.