Rei Kogami - My Dress-Up Darling
Keep in mind that settings may vary slightly between different versions. See below for more details.
When I tested this with different checkpoints and LoRAs, it seemed to work quite well.
Illustrious:
A LoRA weight of 0.9 works great, though you can adjust the strength as you prefer.
Prompts I usually used:
rei_kogami, short hair, black hair, blue eyes, serafuku, white sailor collar, black shirt, black skirt, pleated skirt, white neckerchief,rei_kogami, short hair, black hair, blue eyes, black collared shirt, white vest, white suit, white suit jacket, white suit pants, white tie, colorful boutonniere,