I like it, but so far I've only found negative reviews of it. The most enthusiastic I've seen is "it's a trainwreck, it's GREAT" from someone who thinks it's terrible but had a blast anyway. Personally, though, I'm puzzled by the bashing. It's a dramatic, distinctive show. It's messy, but I like the dilemmas it's built around.
The show has unusual origins. It's based on a role-playing game session between five writers, Gen Urobuchi, Kinoko Nasu, Izuki Kogyoku, Ryougo Narita and Simadoriru. They were playing a game called Red Dragon, which is also part of this small multimedia franchise. There's also a board game and a smartphone game.
What this means for the anime is lots of underused worldbuilding, characters created by different writers and a plot that doesn't always make sense. The story's set in the island kingdom of Nil Kamui. Recently it got invaded by its neighbour, Kouran, but fortunately it had an ally! Donatia would come to its aid, wouldn't it? Um, no. Donatia sat there and watched, before eventually coming in and carving up what remained for itself. Nil Kamui's map now resembles the French flag, with Kouran having taken the blue bit, Donatia the red bit and the Nil Kamui survivors huddled in the white in the middle.
There's something interesting in that, for a start. They don't push this parallel very far, but metaphorically Kouran is China, Donatia is America and Nil Kamui is Japan.
KOURAN - colours: red + black, sometimes with yellow trimmings. (This isn't a brilliant fit for the Chinese flag, but it's not a million miles away either.) It's a "giant, ancient, covetous" country that wants to invade and dominate. (This is a good description of China and its attitude towards its neighbours and/or invaded territories, e.g. Taiwan, Tibet, Xinjiang and pretty much any country that owns an island in the South China Sea.) People from Kouran often have Chinese names, like Lou Zhenhua, Shou Ren, etc. The word "kouran" in Japanese means "disturbance, perturbation, derangement".
DONATIA - colours: red, white and blue. You don't need me to remind you what the American flag looks like. People from Donatia have names like Meryl Sherbet, Enumael Meschwitz and Sir Swallow and they're liable to be merchants, bankrupts, etc. Donatia had promised to defend Nil Kamui (just as the U.S. has defence treaties with Japan) but in fact just stood back self-servingly as soon as anything happened (which I'd call a fair description of the Obama administration's foreign policy, e.g. in Syria... although in fairness he's done much better with non-conflict situations, e.g. Iran.) Donatia wants to set up a puppet government in Nil Kamui (and America once had one of those in Japan). If you say "donatta" in Japanese, this means "shouted in an angry voice, had a shouting match", so that's the American political process covered too.
NIL KAMUI - colours: red and white, like the Japanese flag. People from Nil Kamui have Japanese names like Ibuki, Inori and Fugaki, while the country's name in Japanese could mean "resembles God". Ahem. They also have dangerous nationalists.
These parallels are useful because it helps one keep track of the worldbuilding, because the script isn't helping much. I'd have liked more politics. The countries themselves don't have much presence in the story. Their agents are quite busy, but I didn't really get much impression of Kouran's hand in events or of what its government was trying to do. Instead I met a bunch of people from that country, which isn't the same thing. They're individuals. They have their own motives. Sometimes they're working for the Kouran government and are trying to advance their country's interests, but I didn't get the impression that Kouran itself was a player in events.
I don't mind, really. It's understandable, but perhaps a bit of a waste.
The main character is a boy with a curse. There are three characters with curses, one from each country. Our hero, Ibuki, is the heir to Nil Kamui's throne (which doesn't mean so much these days) and so has a link with the Red Dragon. Every country has a dragon. Ibuki can ask his dragon to kill any one person with 100% guaranteed success... but every time he does this, the price is the life of a dear friend. You'd expect this to be a villain's power. Ibuki's the hero. He doesn't like it much. If you're looking for a kick-ass action hero who names names and laughs at fear, then you're going to be disappointed in Ibuki. I'd guess he's about twelve? I like Ibuki and what the character's exploring, but not everyone agrees with me.
Donatia's cursed hero is Sir Swallow, who destroys everything he touches. He might have been my favourite character, actually, along with his grumpy but faithful companion, Meryl. He's got a traumatic backstory.
Finally Kouran's cursed character is Lou Zhenhua, who owns a soul-drinking vampire blood sword and simply loves feeding it. She's a psychopath, although in fairness her sword bewitches people and she's clearly under the influence. She's still a kill-crazy sadist, though. (There are two luridly evil bastards in this series and they're both from Kouran with big boobs.)
The plot's dramatic, but it doesn't always hang together. Or, if it does, then the explanations aren't very clear. I'm open to the possibility that ep.6 and ep.7 make sense, but what those episodes definitely aren't doing is convey things clearly to the audience. There's a missing arm that I only noticed when they did a flashback of the ambiguously drawn shot, with dialogue to explain what we were looking at. I'd assumed she was just injured or something. Similarly there are lots of characters and you've got to keep track of the dead ones too.
The ending's... not unsatisfying, but it leaves things open a bit. I wouldn't have minded a little more closure. There's symmetry with the cursed three, but there's another character whose story could have been taken a bit further.
I like each episode's final screen, though. It's a picture of our hero and his friends, with the dead ones coloured red and crossed out. It's like a death countdown.
As far as I can tell, this isn't a popular show. If you watch it, I presume odds are you'll dislike it. It lacks clarity, both in conveying information to the audience and in not being cluttered. It's a story about the powerless heir to a powerless kingdom who's trying to avoid using his only power, because it horrifies him. However I think its central questions are strong, clear and dramatic. It's memorable. I find Ibuki's dilemmas compelling. I'm glad I saw it.
"A friend must be killed to save another."