Death Parade is a unique series. The basic premise is that when people die, they are transported two at a time by elevators to a bar, where they play a game against each other with their lives at stake. The people don't remember their pasts or their deaths, so they think they are playing with their lives at stake. The choice of game is decided by a roulette spin, so many different games are played during the series. The fact that the participants’ lives are at stake brings out all the hidden intentions and flaws in their personalities. The bartenders judge them based on their responses to the extreme games, and then one participant goes to hell (the endless void and becomes nothing) and the other participant goes to heaven (is reincarnated back into the world). The bartenders refer to themselves as arbiters, and they have no human feelings or emotions, being essentially puppet judges.
The story follows a few of the different bartenders, most specifically Decim, the tender of the bar “Quindecim”. Decim is new to his arbiter position and just learning it. Assisting Decim in his work is a black-haired human woman named Chiyuki, although she doesn’t remember her name or past until very late in the series. Besides assisting Decim, Chiyuki is learning how the arbiters judge humans by observing Decim, and seems to be there because Decim could not judge her.
The person in charge of Decim and several other arbiters is a senior arbiter named Nona who looks like a little girl. And the being in charge of the entire afterlife system is an old man figure, or alleged god, named Oculus. Oculus spends his time playing galactic pool and keeping an eye on the system. The background story that you pick up as the series progresses is that Nona has decided that the arbiters need human feelings and emotions in order to judge humans. Oculus is completely against this, stating that arbiters must be non-feeling puppets.
So Nona has been secretly creating her arbiter puppets with the ability to have human feelings, including Decim and Ginti (another arbiter in another bar). Oculus doesn't know, but Nona talks about it to other senior arbiters, including one named Quin, who was the original arbiter in Quindecim before Decim came along and now runs the afterlife information bureau, supplying people’s memories to the arbiters. Nona is also responsible for Chiyuki being present with Decim in his bar.
As the human feelings and emotions take hold in Decim and Ginti, they start having difficulty making judgments, as they begin understanding human foibles and feeling human emotions. Chiyuki exacerbates this in Decim, by herself judging on the basis of her own human feelings and emotions, and questioning his judgments.
Eventually Oculus discovers Nona’s plans, but then he tells her to go ahead because it won’t make any difference. Decim struggles with judging Chiyuki until the very end, but he must judge her because being a dead human she cannot survive forever in the afterlife setting. The arbiters can survive because they’re non-human puppets. Decim gains enough human emotions to understand Chiyuki in the end and to send her to be reincarnated, even though it turns out she killed herself in life. So the series leaves you feeling that even though gaining human emotions may make judging harder, it probably makes the arbiters better judges, and that Nona will continue with her experiments.
I wasn’t sure about this series at first, mainly because the first couple of episodes I totally disagreed with who went to heaven and who went to hell. But I stuck, and began to realize the back story and what was taking place. Overall, I liked the series a lot, and the OP is awesome. Even though it started out confusing, I recommend it.