😬 This is a tough question @hardcore-solangelo-19 , for like. Depressing reasons.
I think we can safely say that Makoto doesn't qualify. We have NO idea what her relationship is with her parents, but she never once imagined taking Saiki to meet them, so I'm guessing they're not top of mind and probably also don't qualify.
Yumehara is Teruhashi's first friend so I would WANT her to be the answer... But we just don't get many scenes with them and I can't recall any moment where Teruhashi shows concern for Yumehara's well-being. I mean, she didn't seem to notice at all that Yumehara was dying during the mixer, and when Yumehara defended Teruhashi on the beach, Teruhashi didn't seem to react to that at all??? I think the problem is that Teruhashi is just not used to caring about other people and everyone always bends over backwards to help & entertain her, so she hasn't quite understood the meaning of friendship yet. She'll hang out with Yumehara and Imu when invited and talk with them fairly freely, but she doesn't seem to think about them when they're not around or invite them to do stuff. 🤔
Finally, there's Saiki. He seems like the obvious answer because Teruhashi is obsessed with him. But does she actually value him? That's hard to say, but the evidence kinda leans me towards "no". While Teruhashi makes a big deal about throwing her chocolates out the window to avoid Saiki getting killed by the Kokomins, she later gives his name and descriptions to the Kokomins so that they'll find him for her, making him a HUGE target. She never puts much interest into getting to know him either, taking ages to even figure out his name when they're literally in the same class, and basically only knowing that he likes sweets and says "good grief". She does not seem to react at all to Kokomins almost killing Saiki and Nendo in the library?? She was literally there?? IDK. It seems to me like she values the idea of Saiki in her head a lot more than the reality of Saiki, and I really doubt that she'd value his survival above hers. I mean, she's happy to go to a mixer very late in the series to try to meet dudes of higher social status and wealth than Saiki, and then she wishes he was there instead of thinking that maybe she shouldn't have gone to the mixer at all. He's a comforting presence to her at best, and entertainment at worst, but she just doesn't show much consideration for him. She thinks he's dying of shyness over his love for her and wants him sitting in the corner while richer and handsomer men flirt with her?????
There's Teruhashi's cat but considering she never seems to think about it and it doesn't show up on episodes at her house, she can't love it that much. And if it's Pushy, as the theory goes, then she really can't value the cat too much since she lets it go outdoors unsupervised all day!!!!
So yeah........ I just don't have a good answer to this question, unfortunately. The person Teruhashi values the most is herself, mostly due to her fucked up life circumstances but yeah. IDK much about Dangan Rompa, but I would put her beauty at risk if possible (perhaps by threatening to scar her face or something) and then give her character growth so she's willing to risk that to save her friend(s).




















