Please, please, please, please don't make Octavia a twin. Don't have another Blake sibling. For one, the third child would probably starve because Octavia nearly did and that was when there were only two kids in the family. It wouldn't make sense.
The Blake siblings are Bellamy Blake and Octavia Blake. There's no such thing as a third sibling. It wouldn't make sense for the plot line, and frankly, they would've been caught a lot earlier if there were two more illegal children instead of one.
Just don't do it.
Now, there are many other characters that have apparent siblings as well. Before I get started, I want everyone to know I'm not calling anybody out and if you have a book where the OC is a sibling of one of the main characters. I'm not telling you to remove it. I'm just saying it's a tad bit overdone, and doesn't make sense for most characters.
I don't want to offend anyone when I say that. This is not directed to anyone.
Here's a list of the ones I've seen around Wattpad, and reasons why they wouldn't work
i. Raven Reyes
Raven's mother drank herself to death at what seems to have been a young age. She was an alcoholic. The chances of her having another child is unlikely, not to mention the fact that her husband (if there was one at all) probably left her and Raven when she started drinking.
Also, Raven, even when being an only child, almost starved to death because her mom took her rations in exchange for alcohol. Having another child wouldn't even work considering she wouldn't make it past being a toddler with the way their mother would treat them.
ii. Finn Collins
Finn gave a good portion of his rations to Raven so she could survive. He saved her life. If he had an illegal sibling, this wouldn't have been possible. He probably would have helped Raven any way he could, but he would also have to make sure his sibling was fed. It just wouldn't be possible.
iii. Harper McIntyre
Honestly, we know basically nothing about Harper except the fact that her dad died when she was little from a terminal illness. Now, judging by the fact that she was a little girl, he was probably sick a long time before that. Unless Harper had a twin, which wouldn't work because the Ark would obviously know if another child came out after Harper, her dad was probably too sick to even have another child, let alone care for it.
iv. Clarke Griffin
Abby is apart of the Council, and a highly respected member of it. She works as one of the head surgeons in the medical facility. Jake works as one of the head mechanics/engineers, meaning he knows about the risks of having a second child more than anybody. The chances of them breaking the law and having another kid, the chances of them chancing it with this, is very unlikely. They would never risk their lives, or Clarke's, by having another kid.
Besides, they're close friends with Thelonious and Wells Jaha. He comes over to their house all the time, and he's the Chancellor. They would get caught very quickly.
v. Monty Green
There's not much known about Monty's father, either, except that he died protecting the children from Azgeda when they landed on the Ground. We know things about Hannah, Monty's mother, however. She's a very rule abiding woman. She listens to her Chancellor, even when it was Pike, and when her mind is set on one thing it rarely changes.
She loves her son, too. That's obvious. Like Clarke's mom, she wouldn't risk having another child and breaking the rules. She wouldn't risk ruining Monty's life with the need to care for a little brother or sister. She wouldn't do it.
vi. Jasper Jordan
I mean, this one is kind of hard. If you can come up with a good enough idea, which I'm sure you can, Jasper having a little brother or sister might work. I wouldn't recommend it, though, because as any Ark citizen, they wouldn't have another child unless they have nothing to lose and they live in the poor section of the ship, which Jasper doesn't. You'd also have to make parents exist, which means coming up with two more people.
Besides, twins don't make sense! The Ark would have the first child documented but not the one right after? No, the Ark is very precise with these things. Unless the pregnant woman was very persistent and had one baby and another at their complex, which is basically impossible, it just wouldn't happen.
Unless they put the second child straight in lock-up, or into a foster family until the age of three or five and then took them to lock-up until they were eighteen or something, but even that's a stretch.
Now, I'm not saying that you have to delete your book because of these things. If anything, just continue it with an open mind. Not gonna lie, some of this books are really good, but these are just things that wouldn't make sense.
