Black Paradox follows four members of an online suicide pact who fail their first attempt at suicide and, except for one member, survive their second one. The deceased member, Piitan, was the only member to actually swallow sleeping pills. He was resurrected for a short time, during which he coughed up large amounts of stones, which another member, Baracchi, determined to be extremely valuable and hitherto unidentified. Baracchi and Taburou, another member of the four, start planning to get rich with the stones, and cooperate with Baracchi's doctor Suka, while the nurse Marusou, who is a colleague of Suka and the final member of the pact, tries to stop them.

In my opinion, this story was not the best. The premise of the story was interesting, but the plot was, by and large, fairly simple and, by the middle of the story, predictable and rather forgettable. Thankfully, the important reveal at the end added quite a bit of depth to the story. I actually liked the doppelganger subplot at the beginning of the story, but apart from Piitan's doppelganger, this was never expanded on much; in particular, Baracchi's doppelganger remains a complete mystery even after I've finished the book. I would have loved to have seen the doppelganger subplot expanded on and perhaps connected somehow to the stones. It would have been nice, too, to see more of the 'paradise'.

The body horror in this manga was very tame. There are somewhat horrifying scenes like Piitan's explosion, the balls falling out of Baracchi's face, or the travelling into and from 'paradise' in general, but don't expect another Uzumaki.

The characterisation was not the strongest, but good enough. Piitan is a gloomy person from beginning to end. Suka is a manipulative, two-faced liar whom you'd love to punch in the face. Baracchi and Taburou are portrayed as extremely greedy, although Taburou lets fear take over greed pretty easily. Marusou, the closest the manga has to having a protagonist, is the only character painted in a positive light, as the only person who cared about Piitan's safety and the only person wary of the possible risks of exploiting the stones. She was also the only to go through clear character development, though this was because of a physical change to her brain.

There were two other stories in the volume, one short and the other extremely short. Neither were really of enough substance to be particularly remarkable, but the Franken-pelican in the second story was pretty imaginative. Overall, the manga had an interesting premise that kept me reading, but was ultimately fairly predictable and could have expanded more on many of its plot elements.