WMG / Black Bullet

Stage 5 Gastrea come from Cursed Children

To this troper's knowledge, the source of Stage 5's is unknown to the present. Gastrea up until Stage 4 develop gradually, slowly "evolving" into higher forms until they reach Stage 4. However, no one's really certain how someone becomes a Stage 5 or, if it is again a gradual evolution, what causes the majority to stop at or before Stage 4. One possibility is that this higher development is connected to the unique infection, long incubation and partial resistance found in Cursed Children. There's certainly evidence that at least Scorpio was a mere child, given the implication that she/it came after an old tricycle that came from her/its town of origin.

Enju Aihara will find out about her real corrosion rate and her eventual fate that she'll turn into a Gastrea

Rentaro can't keep up with his utilitarian ethics on maintaining Enju's happiness and hiding the truth from Enju. He'll eventually have put his utilitarian ethics (like he did during the Fugitive arch) and his relationship to Enju to the test and have to tell Enju the truth about the fate of most cursed children and her corrosion rate. How Enju will react will depend on how she will find out. But remember that Enju happens to be one of the most kind-hearted characters in the series who is willing to forgive everyone.

A religious fanatic group will be introduced as an antagonist group led by a Sinister Minister who calls for genocide on Cursed Children

Considering the left-leaning nature of the series, it's most likely that a religious fanatic group who wants to call for a genocide against cursed children will be introduced as showing the evils of religion in regards to Fantastic Racism. Bonus points if Enju and Tina gets kidnapped by the said group and the said group rapes Tina and Enju.

A Malcolm Xerox Anti-Hero for cursed children rights will be introduced.

Since Seitenshi mostly serves as a Martin Luther King Jr. type figure towards the cursed children, it'll make sense that the series will introduce a Malcolm X type Anti-Hero who shares the same goals as Seitenshi. However, unlike Seitenshi who wants to change society through peaceful means, the Anti-Hero is willing to resort to violence and terrorism to achieve this goal. He will most likely will lead a terrorist group (mostly a communist group) consisting of cursed children and former Promotors/Initiators who are angry on human society treating the cursed children as trash and feel that Violence is the Only Option to achieve equal rights for the cursed children. The Anti-Hero will try to convince Rentaro and Kisara to join his cause, but as long Enju and Tina are around, they'll make sure that Rentaro and Kisara doesn't join the terrorist group.

This series will end as a Downer Ending at worst, and Bittersweet Ending at best.

At worst, Enju and Tina gets killed off and Rentaro takes his utilitarianism to extreme and the world will end up being worse. At best, it'll be a Bittersweet Ending, with either Enju and Tina surviving and completely immune from turning into the Gastrea, or some Heroic Sacrifice is involved.

Enju and Tina will eventually turn into the Gastrea or killed off brutally

.Considering the very status Enju and Tina are in with their high corrosion rate, this may eventually happen unless there is a Find the Cure! story arch.

There will be a coup that involves overthrowing Seitenshi.

Since there will be many people who oppose Seitenshi's implementation of equal rights for cursed children, it'll be no surprise if a coup overthrowing Seitenshi and Rentaro and co. being captured and sent to be executed will be involved. Bonus points if the instigator of the coup will either be Kikunojou Tendo, Takuto Yasuwaki, or Sōgen Saitake and his Right-Wing Militia Fanatic is involved in the coup.

There will be a Villain Team-Up between the Sougen Saitake's Right-Wing Militia Fanatic, Ayn Rand, and Hiruko pair and put Rentaro in a Sadistic Choice scenario.

All three of these villains will have some grudge against Rentaro or want to ruin Rentaro's life. They'll put Rentaro in a Sadistic Choice situation where they kidnap Enju and Tina, tie them up, and have Rentaro make a choice: either save millions of lives in some faraway city or save Enju and Tina. And they'll make sure either choice will make Rentaro fail. If he tries to rescue Enju and Tina, he'll find out there are different cursed children there and Enju and Tina is revealed to be somewhere else and killed off. If he tries to save the city, Enju and Tina are not only killed off, but the bomb will activate and kill everyone in the city. In other words, The Bad Guy Wins and Rentaro enters his path of darkness.

Rentaro will become a Kiritsugu Emiya type Anti-Hero.

If anything bad happens to Enju or Tina, this will be enough for Rentaro to enter his path of darkness and take his utilitarianism to the extreme.

There are male cursed children, they just happen to be clones of cursed children.

The light novels stated that all cursed children are female. That being said, it's possible that a cloning story arch will be involved and male cursed children will be introduced (who happen to be clones of the cursed children). It'll turn out that Enju and Tina have "brothers" who happen to be clones of themselves. The clones are made to replinish the loses in the battle against the Gastrea and the clones are meant to be stronger than the cursed children. Not to mention, unlike the cursed children, the clones don't turn into the Gastrea at all.