A Name I Haven't Thought of Yet: A Female Sentinel, a Male Guide, and a Chaotic Sibling Romance

Just jotting down an idea for now. The title and blurb still need work, but the premise will stay the same.

The heroine is the strongest sentinel in the White Tower.

Then disaster strikes: her guide husband dies, leaving behind two younger brothers, both guides.

The second brother looks nearly identical to his elder brother, and is just as gentle and steady in temperament.

The organization assigns him to guide his sister-in-law. But when the heroine sees him, she calls out her dead husband's name and loses control of her mind.

The third brother has just graduated from military academy. Usually arrogant and unruly, he's obedient only in front of his sister-in-law. When he hears that his second brother's guiding session with her has failed, he's forced to step in at the last minute.

That trip reveals a huge secret: his sister-in-law never loved his elder brother. She accepted their bond because his family's standing could secure more resources.

The third brother begins to hate her for her faithlessness. But when he watches her eyes turn red and endures her frenzied bites, he feels a secret sense of relief.

...If my elder brother hadn't died, would I never have seen this side of her?

-

Meanwhile, the second brother discovers that his sister-in-law had refused to see him not because he looks like his elder brother.

But because... her mental compatibility with him is even higher than it was with his elder brother.

She resists him because she doesn't want to be healed.

This soldier, who has guarded the White Tower for five years, wants to rest.

The second brother thinks calmly: My elder brother died because of her. Since she's so desperate to rest, she might as well go below and keep him company.

He decides to tempt her, make her addicted to him, cure her, and then have her die outside the White Tower.

But he never expected the first person to stop him would be his younger brother.

And he never expected that, in the end, he himself would forget the vow of revenge he had made.

Theme: To be filled in later.