Oyama Mahiro | 緒山 まひろ | Onii-chan wa Oshimai! | お兄ちゃんはおしまい！

Source: Onii-chan wa Oshimai! (ONIMAI: I'm Now Your Sister!)

Character Description:
Oyama Mahiro was originally a shut-in NEET young man until his sister, Mihari, gave him a suspicious drug that transformed him into a middle school girl. She has long light brown hair (often with pinkish-gradient tips in the anime) featuring a prominent, expressive ahoge (antenna hair). Her eyes are a warm brown. Mahiro’s personality is a mix of gamer-girl lethargy and feminine embarrassment. Her wardrobe transitions from her "shut-in" look, consisting of an oversized blue shirt, to her school-going attire, which includes a white dress shirt, neck ribbon, and a black suspender skirt. She is also frequently seen in her formal school blazer.

🗝️ Core Activation & Physical Traits

Use these base tags to capture Mahiro’s soft, "transformed" aesthetic:

oyama mahiro \(ONIMAI\), 1girl, solo, light brown hair, long hair, ahoge, antenna hair, brown eyes, flat chest, short stature, petite, blushing

👗 Outfit Variations

1. The Gamer Shut-in (Oversized Shirt)
Her most common casual look while playing video games or lounging at home.

oyama mahiro \(ONIMAI\), oversized shirt, blue shirt, long sleeves, bare legs, sitting, gaming headset, messy room background, looking at viewer

2. Middle School Freshman (Suspender Skirt)
The standard uniform for her new life at school.

oyama mahiro \(ONIMAI\), school uniform, white shirt, long sleeves, neck ribbon, black skirt, suspender skirt, white socks, loafers, looking at viewer, standing

3. Winter School Gear (Blazer)
The formal version of her uniform for colder weather or ceremonies.

oyama mahiro \(ONIMAI\), school uniform, blazer, jacket, white shirt, neck ribbon, black skirt, pleated skirt, school hallway background, holding school bag

4. Morning Panic (Comedic Focus)
Focuses on her frequent state of confusion regarding her new body.

oyama mahiro \(ONIMAI\), oversized blue shirt, messy hair, ahoge, looking into mirror, shocked expression, wide eyes, blushing, cinematic lighting, sharp focus

⚙️ Recommended Settings & Tips

• LoRA Weight: 0.85 - 1.0 (To ensure the ahoge and the soft, rounded art style of ONIMAI are maintained. The pinkish-gradient in her hair is often baked into Mahiro LoRAs).
• Base Models: Optimized for Illustrious XL and Pony Diffusion V6 XL.
• Environment: Works best in messy bedroom, school classroom, modern kitchen, or video game center.
• Pro-Tip: Mahiro is defined by her "inner NEET" personality. Use expressions like embarrassed, shy, nervous, or lazy. To get the specific suspender skirt look, ensure the suspenders tag is included so the AI doesn't just render a high-waisted skirt.

📷 Sample Prompt (SFW)

score_9, score_8_up, score_7_up, masterpiece, 1girl, solo, oyama mahiro \(ONIMAI\), long light brown hair, ahoge, brown eyes, school uniform, white shirt, neck ribbon, black suspender skirt, white socks, standing in a sunlit classroom, looking at viewer, shy smile, cinematic lighting, sharp focus, anime style

🔞 Sample Prompt (NSFW)

score_9, score_8_up, score_7_up, masterpiece, 1girl, solo, oyama mahiro \(ONIMAI\), light brown hair, ahoge, brown eyes, flat chest, petite, nude, shibari, rope bondage, collar, show pussy, spreading pussy, nipples, small breasts, torn clothes, torn oversized blue shirt, blushing, crying, sweating, struggle, messy bedroom background, high quality, highly detailed