also btw if you think furina is a deep well written character, but columbina is bland and boring, then i would ask you to consider for a second if maybe you just paid more attention to furina bc she's loud and extraverted and bina is quiet and introverted.
btw this is not a dig at fru fru, i love her, this is me drawing parallels to help ppl better understand, bc they basically have parallel themes, furina is a fake goddess whose ppl force her into a role of what they perceive their goddess should be like while real goddess is right there in front of them being ignored (oratrice), and bina is a real goddess, whose ppl forced her into a role of what they perceive their goddess should be like while worshipping false idol of the fake moon
and like the difference is that we learn furina's real story in one dramatic burst where she's shown to express her sadness and depression in conventionally accepted terms like crying, looking visibly sad, etc. while we learn bina's story in small bits slowly and she's never doing any expressive outbursts, bc her way of coping is to distance herself, to close off. but it doesn't make it less sad then just crying
both of these stories are about inherent trauma and alienation of being divinely designated above others from different perspectives and tempers. bina was never given an option of human socialization, she was put above others, yes, but at a condition of giving favors which literally drained her health, and every time she tried to reach out and engage with others, like helping a kid, ppl treated it like divine sign and tried to exploit it.
so she came to her transactional understanding, that ppl will always want divine favors from her for ANYTHING, this is why she left nod krai and joined fatui, bc yes, tsaritsa only wanted her only for her power, but at least it was a clear cut deal and not a slow drain of energy by people who claimed to love her, but didn't care to know her. sandrone says that when she just joined, bina would constantly go to tsaritsa and ask what should she do, but she was given no tasks until she gave up, exactly bc bina was eager to pay the price as soon as possible. this is why when she just met the traveler, she bargains with her blessings for everything and refuses to even take sweets for free.
and to be fair to scara and childe voice lines, at this point she was weird and kinda creepy. she was a goddess of immense power, with zero socialization and discouraged from empathy. like arle tried to intimidate her by appearing right behind her back, but instead of being scared, bina thought its a game that friends play, and did it to arle herself which arle thought was not possible before. when you see this sweet looking signing girl angel jump scaring arlecchino, you would think she's hiding scary nature. she sang her weird songs under sandrone's doors when sandrone was cussing her out and no wonder everyone thought she's nuts, but bina was literally just grasping at any threads of connection that were not transactional
there is a short, but very revealing dialogue between bina and sandrone where bina says oh, i wish there was a place where no one asked anything of me, and we could just sit together whenever we wanted and drink tea. and sandrone is like, are you stupid??? why would something like this exist??? and bina is like yeah, you're right. like. these girls are so far from normal they can't even see it, they don't even know how fucked up they are. but i guess bc paimon didn't show up and spell it out, many ppl missed that its fucked up
this transactional understanding of a hostile world was probably what initially brought her and dotorre closer, but bc bina is not self-loathing like scara, she soon understood he means to exploit her too and distanced herself from him, when dotorre legit didn't see the problem bc to him its the norm and its the transactional exploitation of each other that he offers to the traveler.
and this is just the start of bina's arc, she goes thru slow growth of not caring about others, like at first act she saves the group just bc sandrone and partially the traveler is there, and she's somewhat surprised that lauma and flins thank her for the rescue bc she didn't care about them, then to care about her little group of friends and shedding transactional nature of interactions, and then to understanding that all people are important and valuable, even if they are not your personal friends, then to be ready to sacrifice herself for nod krai with no promised repayment that contrasts her to dotorre's transactional philosophy. and at the festival when bina gives everyone personalized candy arle says you wouldn't do anything like that before, you changed so much, and i like it better. like. she learned to pay attention and give attention that is not based on her divine power, but on other ppl's tastes! and she learned to build connections thru that!
and then there is a theme of her blindfold, her closing herself from the world not just bc ppl exploited her, but bc the world is built on the lies and she loathed to see them, but then her deciding that the true smiles of her friends were worth seeing even under false skies?
like there is so much going on with bina, i didn't even expand on her complicated relationship with scions and lauma or her troll sense of humor that comes out in her flirting with sandrone, but my point is that if you think she's bland and has no character, like legit just reconsider what "character" you pay attention