Mija is a Namija living in Gensokyo’s underground alongside Kemu, spending her days playing with other youkai and visiting the surface every once in a while. Young for a youkai, she’s always learning from those around her, but she’s also considered a good teacher herself as she’s straightforward with her advice.

Mija is a very conscientious person who can read rooms too well even if the adults try to hide things from her. She's mature enough to hardly cry or appear childish, easily entrusted with difficult tasks. She can point out others' insecurities quick into meeting them and ensures she doesn't bring attention to it. She's kind for the most part. She's somewhat of a reserved or shy person, appearing more introverted than Kemu in that regard. When there's guests, she peers at them curiously but runs off if noticed. She has seen many conversations like anyone else, but becomes at a loss of words when she's put on the spot or having a one on one with someone she isn't familiar with. She can be blunt but that's her honesty as a child showing. While she's wary of others' worries, if it's a stubborn person around her like Marmoris, she sets her boundaries and will always say if she's upset. For a kid she has an intimidating stare when she's displeased, like "😐".

Mija's earliest memories were rooted in Gensokyo's underground, Former Hell where a plethora of youkai ran about and shared each others' company without restraints. Without any particular guardian or family, she felt drawn towards Kemu who lived by herself, an enenra who'd been around for many many years. Being far younger than most youkai, still under the age of an adult, she began living with Kemu with the intent of staying around for generations given their long lives. Through their shared living arrangements, the two shared a bond that could be considered that of a family's. Like Kemu, Mija was a quiet and calm person, a child who listened to those older than her as she navigated the world around her. She was attentive, learning by seeing, but with Kemu she could see that she was particularly wary of the mess she'd leave behind. If Enenras were susceptible to being messy with the smoke and soot they emitted, Mija knew she'd have to adjust to it, and accepted that trait as it was. In fact, she liked cleaning enough she'd do it in Kemu's stead, having her back with that unpredictable nature of hers.

When her caretaker occasionally left to accompany a friend on the surface, naturally, Mija was interested as she'd never seen it in person. Once a couple trips went well, Mija was taken to the surface to see the landscape, and to meet Kemu's partner, Marmoris. While she was intimidated at first by the Tengu's tall appearance, the two grew close by having Kemu as their bridge, a person they both respected and cared for. Still, whenever they'd get to visit, Mija was more interested in seeing the surface than anyone in particular. Gensokyo was vast with different climates and landscapes, always a surprise to Mija. It inspired her to write more poetry perhaps, but bringing her writing materials made her feel a bit embarrassed given that Marmoris was an exceptional writer herself, and she'd surely be nosy about her hobby. Even so, she doesn't feel that she wastes any opportunities for inspiration when she meets many of the surface youkai and beings, occasionally running into the Goddesses on Youkai Mountain or a couple fairies. Seeing how the world differs in the eyes of others, there's countless perspectives she can come across without having to read about it, instead being told stories by those she meets.

Nowadays she is used to Kemu and Marmoris planning to meet the other, occasionally seeing the Tengu stay with them for a couple days, or heading up herself with Kemu to visit the Tengu's home. With the noise from all the hectic Tengu, Mija certainly prefers staying in other areas like inns(especially if her cat can come), but getting to spend time with either Marmoris or Kemu is still as enjoyable as ever. As she becomes older, learning to hone the predetermined skills she has as a Namija, she hopes she can be a youkai that's deemed interesting. For those with long lives in their world, perhaps boredom is their greatest enemy. She doesn't feel unsatisfied right now, grateful for the interesting days ahead of her, so she'll keep doing what she's doing.

"I didn't miss you THAT much when you were gone. Wha-- Miso must have carried my blanket to your bed. I swear!" A dynamic thinly bordering between a parent and child, or that of sisters. The two consider the other like family, relying on the other on tasks and making meals together. Mija is fairly mature, or tries to appear that way, to Kemu, cleaning up after her and offering to do tasks like cooking occasionally. Still, she prefers when Kemu teaches her something by hand and they're both creating something together. Their level of respect is on another level.

"You're our guest, please, sleep in my room. I'll share a room with Kemu-- Wait!!! I called dibs first!! No fair-- Kemu!!!!!"" Their relationship appears more like a little sibling and the older one that teases, that being the only way Marmoris can make her show her more childish and honest sides. There's a little bit of a one sided rivalry by Mija where she gets jealous of Marmoris taking up a lot of Kemu's time, but luckily Kemu prefers to involve everyone than leave someone out. It's uncomfy to all share a bed together though, even with the cat joining.

"...You're a lot like Miss Kimyoumaru. You don't have to kneel to talk to me. Huh?! You don't have to pick me up either! Hey!!" A duo that can get along but also not when Mija is feeling annoyed over being treated too much like a little kid. Toyo likes to give her a lot of treats and dote on her, especially telling her stories about Marmoris, coming up with fears that aren't true. When Mija tries to make fun of Marmoris over those falsehoods, Toyo just laughs watching both of them become confused. Mija usually doesn't talk to Toyo unless she is spoken to first, since Toyo does come off a bit scary and mischevious, so her mood is hard to read.