Senju Muramasa doesn’t back down on her intention to crush Masamune, and easily dispatches Elf by having the editor inform her just how many more sales she has (14+ mil vs. 2 mil), forcing a quick Elf retreat. Masamune responds with a challenge to his “senpai”: whoever loses the contest will have to do whatever the victor says.
We knew this was the challenge that was coming, it’s just a matter of what Masamune will write, and whether it will be good enough to beat a platinum powerhouse. He decides he’ll convert his little sister novel to a short story, but short stories aren’t his forte.
Enter Elf, who uses her expertise gained by her own strong sales and puts Masamune through a gauntlet of drafts, until he’s got a “passable”, if not yet good enough, manuscript.
Then the enemy pays him a visit, intentionally wearing a school uniform in order to “make a better impression.” You see, she wants Masamune to surrender, and instead agree to “be hers”, i.e. write novels just for her.
Elf and an on-screen Sagiri are suspicious of her appearance in the midst of the contest, but it would seem Muramasa isn’t trying to sabotage her kohai, just make him pivot to something she sees would benefit both sides. She also doesn’t flinch at Elf’s claim she and Masamune are living together.
She comes in, and after briefly getting distracted by a sudden jolt of inspiration forcing her to stop her conversation in the middle and start writing (and she’s left-handed!), tells Masamune what her dream is: to be able to go beyond writing stories she’s rate 100-out-of-100, and create something even she, not just a fan, could rate 1 million out of 100.
She only writes at all because of Masamune, whose battle novels were the only things that moved her to the bottom of her heart. When he shifted to rom-com with the little-sister proposal, and stopped writing her favorite novel, she became a wreck, and only by writing her own stuff could she keep going.
So Muramasa, certain her dream is more important than Masamune’s, once again pleads with him to become “hers” and write only for her, promising she’ll support him and his sister the rest of their lives if that’s what it takes. But Masamune’s dream isn’t just his own, and Sagiri leaves her room to tell Muramasa as much.
Also, Sagiri won’t accept any scenario in which she gives up Masamune for anyone else. She earlier says he’s not allowed to date other girls ever after seeing Elf’s tweet. This is highly unreasonable behavior, but younger sibling jealousy is nothing new or abnormal. Masamune shows a united front with his sister and declines Muramasa’s author, saying he’ll instead get her hooked on his rom-com.
I mean, that’s great and all, but surely Masamune realizes he can’t keep indulging Sagiri’s possessiveness, right? And that any future romantic partner has to be chosen from among girls he’s not related to by marriage? Just asking for a friend…
Masamune ends up winning the contest, because even though Muramasa got 15 more votes, her short story ran double the allowed length, and she was disqualified. Whether this was intentional on her part, or if she simply wrote the number of pages she had to write and didn’t care what happened afterwards, the story was all about her and Masamune.
Like Masamune’s story about his sister, Muramasa’s is a love letter…to him. So now Muramasa is not just in love with his novels, but with him in general. Masamune doesn’t have a satisfying answer: “there’s [already] someone I love.”
It leads me to wonder if Muramasa’s only purpose on the show was to be defeated twice in short order and retreat as Elf did upon hearing about her sales…or if the battle has just begun. Either way, he harem has become really crowded.