#child character

Characters have goals. Authors have ways to stop them from achieving those goals. Characters dislike that. This relationship between characters and their goals is what makes a story. Even in a simple fluff fic where Mira's goal is to brush Siffrin's hair, or Isabeau's goal is to comfort Siffrin from a nightmare. The level of conflict may be null, but the goal exists!!!

The difference when writing child characters lies solely in the reaction. Not the goal. Bonnie's desire to kill the King burns no less bright than their adult family's, and portraying them as being just along for the ride is a no-no. Same goes for the journey after. Bonnie wants to stay with their new family. I'm not saying there's no reason they would ever want to go back to Bambouche permanently, but it would have to be good. Just saying "They have school," "They need stability," does their character a disservice. There should be a real, autonomous reason behind their actions and choices. (If someone forced them to do something they don't want to, thus conflicting with their goal, they will have a reaction to that. Further explained below.)

So, having a goal is the same. But the reaction to having this goal thwarted can be very different.

Kids lack emotional regulation skills and broader context for life. They're very NEW to this whole being alive thing. For example, when you're four, getting denied candy at the check out is one of the worst things you've ever experienced!!! You don't cry because you're entitled, you cry because you haven't developed a tolerance to casual disappointment and sadness yet. Plus, you aren't very attuned to the concept of a future yet, because you barely even have a past. Adults know they'll get candy some day. Kids don't really get that!!! They feel like they're being told they'll never have this thing they want ever!!!!! Tldr, kids reactions are intense because they lack experience and context.

Applying this back to Bonnie's reactions to having their goals thwarted: You need to know two things:

Bonnie can't control their emotions.*

Bonnie tends to default to anger.

(*They are old enough by now they can tolerate things like, not getting candy at the grocery store. But they can't hide their emotions about Frin's eye, or their frustration when something on their quest through the House goes wrong.)

Therefore, when Bonnie can't achieve their goal, whether that's, help beat the King, help Frin, don't let your family get hurt, cook a dinner--they get super angry, teary, and loud.

Example: Post canon fic where the party is trying to get Siffrin to open up, and they keep deflecting. None of the party like that. But while the adult party members will keep trying to foster a supportive environment and express their desire to help, Bonnie might start yelling at him or crying about it, because they're upset!!! They don't get that if they're patient and quiet Siffrin will open up in, say, a month. They're like, ten! That takes too long!!!! Frin is hurting now and they want to help and he's making it hard for them to do that and they! can't! handle that! Their goal is the same as everyone else's, but they just don't have the context and coping skills the others have, so they cry and scream and make a ruckus.

"Okay. That makes sense. But what about developmentally?"

Bonnie is a preteen. At this point, they can do things like, understand metaphors and symbolism, pick up on subtext in conversations, understand situations aren't all black and white. But they sometimes lack context. For instance, look in the writing room with the orange poem. Bonnie recognizes the writer is the orange, but, lacking the context of turmoil in relationships the poem seems to hint at, they suggest the ending should be "Peel an orange open, I die!" Because if you get peeled open, you die, obviously.

So if you're writing a fic and, say, the party is hinting to each other Siffrin is very upset after the loops, Bonnie's immediate thought won't be, I guess Siffrin is traumatized and needs therapy, it'll be, oh, I should go make them their favorite food to cheer them up! Bonnie WILL recognize if Siffrin's pattern of sadness keeps going, though, because they're getting context by living through it.

"But my fic is about self harm, suicide, etc."

Bonnie's goal is to see their family safe and happy, and they will react negatively to being booted from the conversation. Someone is going to have to talk them into leaving and promise them they can help later.

And while obviously it's not healthy for Bonnie to be taking care of a Siffrin in crisis, as that's not their responsibility and Siffrin would hate it, completely hiding this from them is not in their best interests either. Making the concepts of self harm and suicide taboo scares kids and makes them unlikely to reach out for help if they struggle with something similar in the future. (And considering what Bon's been through, they could absolutely struggle with that sooner rather than later.) Plus, saying "Frin is going through something so horrible you can't even know about it because it's That Bad" will likely lead them to catastrophizing. Explaining "This is what Frin is going through, this is how we're helping, we know this is scary and we are here for you" is much much better for Bonnie. Of course, if this being hidden from Bonnie serves a narrative purpose (I'm working on a fic about that actually,) that's part of the story and falls under "depiction not endorsement."

To summarize, they should have goals and thoughts and feelings the same as the rest of their party. These goals, thoughts, and feelings should be treated by the author as just as important as their family members'. And when something goes wrong with those goals, thoughts, and feelings, they should react intensely and emotionally, typically with anger.