Demon Slayer: If I Say You’ll Live, You’ll Live

[Signed] + [Slow-paced long novel] + [Slightly irresistible to everyone] + [Some canon couples stay together] + [Main pairing: Sabito] + [Everyone else has romantic tension, except canon couples] + [Happy ending] + [Multiple-world endings in the bonus chapters]

Please ignore my pen name QAQ. I was young and reckless, and only realized later that I couldn't change it 0∧0

The heroine is Luo Xi. The main pairing is Sabito, with romantic tension with everyone else except for a few canon couples. (The canon couples that stay together are mostly mentioned in the first paragraph of Chapter One. I won't break up some of the later couples either.)

Everyone survives, including the Master.

Luo Xi: She won't let regrets come true.

Background:

The sole surviving descendant of a family of shrine priests. Everyone else died. She created Life Breathing, a branch of Water Breathing.

In the early part, she's with the Demon Slayer Corps, the Pillar of Life. Her Breathing Style has healing properties: she can heal herself and others. (She discovers this midway through the story. The Master is only partway through treatment when he turns into a demon, or perhaps they had discussed it beforehand.)

In the middle and later parts, she becomes a demon. At first, Muzan humiliates her, but later realizes he can't kill her.

After the Infinity Castle, she joins the Demon Slayer Corps in killing the Demon King Muzan, but Muzan gives his blood to her and Tanjiro. (I guess the two of them nearly became invincible.)

Then Tamayo's medicine turns her back into a human. Basically, the Master lives: the mushroom cloud was halfway through exploding when it was urgently recalled, or you could say he was kept alive.

She's a little saintly, and becomes more so later on.

After that come all sorts of bonus chapters focused on different pairings. I guess they're various kinds of otome stories?

I can't believe this. What are these weird tags?

Those tags were added by the site itself. I originally didn't add so many.

I only tagged it as an anime spin-off and fan fiction. The rest were added by the site, so don't blame me.