Krovyu

*I do not mean to undermine the existing review, I just wanted to add one of my own.*

Warning - this manga has high gore content, and it is not "cleverly censored". There is a reason this is listed for having "mature content". It is pretty disturbing, but truly interesting. If you're into gore style horror and a whirlwind plot that grows more complex as more is revealed as chapters pass - Pupa is something I recommend to you!

  As the reader, you're introduced to the back story from the viewpoint of Utsutsu by way of adorable teddy bears in tragic scenes. You move on to Utsutsu and his "sister" going about their lives together without their parents... It is clear Utsutsu has a sister complex and Yume is very attached to Utsutsu as well, but in a way that's less incestual and more like a very loyal and loving dog.

 Their father is a Yakuza, Shiro Onijima, whom people in the community fear greatly. Their mother is Sachiko Hasegawa, whom Shiro married when she became pregnant with their son at the age of 16. Their relationship becomes extremely violent when Shiro returns after a 5 year trip to see a SECOND child, whom he assumes was born of an affair, which is probably why he turned so hard towards his once cherished love.

    One day, Utsutsu and Yume walk home from school and bump into a strange woman who warns them to "leave before the red butterflies come". Utsutsu then sees their father parked waiting for them - he has Yume go on ahead to the park without him...This is when tragedy strikes, or so it seems from Utsutsu's point of view...

                                     I found the storyline intriguing, overall, but a little slow paced for my liking. I could have seen this series lasting a bit longer, or at the very least
I expected a lot more from it's anime adaption...
If you don't have a weak stomach - you may find this just as interesting as I did.

In closing I'd like to mention I'd be happy to explain
any confusing things in the back-story or overall.
*Good luck finding the "completed" series, it seems to have fallen
through the cracks - such a pitty.*
Stay Creepy,
~Krovyu

***SPOILER ALERT***
The incestual undertones, portrayed by Yume feasting on Utsutsu in a way that makes it seem as if it's an euphoric experience for him, are a little weirder than simple sibbling incest - Yume is a genetic copy of Utsutsu's mother Sachiko.
Yume did NOT get "infected" on that day in the park, she IS a Pupa and she simply
awakened and left her shell. Like a larva transforming into a butterfly.
Yume is a "monster" - she is not human.
The reason Sachiko gave her the name Yume was because the events that transpired after Utsutsu's birth surely had to have been some horrible nightmare, only a dream - right? Sachiko feared Yume would harm her precious Utsutsu and has a difficult time keeping her sanity due to various events that occur further proving Yume is a monster. Shiro thinks Yume is a bastard child and takes out his rage and feelings of betrayal out on Sachiko as well as the children. Perhaps the reason he even beat on Utsutsu was because of Yume's existence Shiro may have wondered if he was even his son either because surely she wasn't his daughter.
Sachiko is believed, by the duo, to have left with another man.
In reality, she finally lost her mind and remains in a hospital over a pupa research lab.
Shiro truly did abandon them, but in his own twisted way it is clear he still cared
about his wife and children. (It truly seemed like relief hit him when he heard ths story of how Yume came to exist, knowing his beloved had indeed been faithful. Maybe I was reading into things too much, and his facial expressions, but that's how I saw things.)