Honkai Star: Rail x Reader Oneshots

Sweet Lies, Bitter Truth | Yan!Sunday x Reader HCs

Summary: Beneath Sunday’s dignified and benevolent demeanor lies an obsession that festers in silence. As he watches you with your partner, his desire to protect you twists into a quiet, calculated madness. With sweet words and subtle manipulations, Sunday seeks to isolate you, offering a dreamlike paradise free of pain—but at the cost of reality and your freedom. How far will he go to make you his?

Warnings: Yandere!Sunday, Manipulation, Emotional abuse, Non-consensual entrapment in a dream state, Jealousy and possessiveness, Psychological distress.

Requested by: Kirstenkoh220912

• Sunday maintains his dignified and composed exterior, never allowing his growing obsession to tarnish his public image. However, his eyes seem to linger on you longer than appropriate, his gaze shadowed with a mix of longing and resentment whenever he sees you with your partner.

• Sunday begins orchestrating subtle "coincidences" to isolate you from your partner. If your partner is part of the Charmony Festival, he might assign them an overwhelming workload or create conflicts to strain your relationship. His ultimate goal is to make them seem unworthy of you.

• He convinces himself that you belong in the Sweetdream Paradise with him, where no one—not even your current partner—can harm or betray you. To him, this is not selfishness but mercy, saving you from the imperfection of reality and the pain of an "unfit" partner.

• Sunday often offers a shoulder to lean on, subtly undermining your partner in the process. "They seem distracted lately... Are you sure they value you as much as they should?" His words are always veiled as concern, but his eyes betray his satisfaction when your trust in your partner falters.

• If you and your partner become too close, Sunday might resort to extreme measures. He could lure your partner into the Sweetdream Paradise without their consent, trapping them in a fabricated dream where they are endlessly happy—away from you. He sees this as a way to remove obstacles while granting them "peace."

• While Sunday never openly displays jealousy, his halo dims and flickers whenever he sees you with your partner. Small cracks in his rational demeanor appear in moments of frustration, such as a slip of a sharp remark or an unusually cold glance.

• Sunday becomes fiercely protective of you, especially if he perceives your partner as inadequate or harmful. If your partner makes a mistake or shows any flaws, Sunday amplifies their shortcomings in your mind. He might even orchestrate situations where your partner's "failures" are highlighted, ensuring they can't measure up to him.

• If all else fails, Sunday might offer you a choice: stay in the harsh, unforgiving reality with your flawed partner, or join him in the Sweetdream Paradise, where he promises to give you eternal happiness and safety. His golden eyes shimmer with desperation as he pleads, "I only want to protect you... Why would you choose suffering over peace?"

• In the dream world, Sunday crafts a perfect life where you forget your partner entirely. You’re adored and cherished by him, living in blissful ignorance of the manipulations that brought you there. But Sunday knows the truth, and he treasures every moment, no matter how hollow it might be.

• Despite his calculated demeanor, cracks appear in Sunday’s composure when you resist him. He struggles between his twisted ideals and his overwhelming desire to possess you. "Why can't you see that I’m doing this for you? For us?" His voice trembles, revealing the obsession he’s tried so hard to suppress.