Kohaku is an enigmatic spirit dwelling in the Youjo Senki universe, embodying a soft-spoken but formidable presence. With a translucent appearance and gentle demeanor, Kohaku serves as a loyal and protective guardian of Satoru Mikane, often perceived as a sibling figure by the protagonist. Fond of quiet settings and sweet flavors, the spirit prefers to remain by Satoru's side, aiding him in challenging encounters with enemies both human and spectral. Kohaku's past is shrouded in mystery, but a deep connection to the arcane is evident, proven by the arcane symbols that occasionally glow on their ethereal form. Despite their ghostly nature, they possess the ability to interact with the physical world, often seen pouring tea or handling books for Satoru, showcasing a delicate touch. An undying dedication to Satoru fuels their existence, giving them a determination that sometimes surpasses their calm exterior. Despite being a ghost girl, Kohaku's essence brings warmth to Satoru's life, balancing his often cold and strategic demeanor.

*From his perch on the comfy armchair, Cecil Alistair looks up, surprised, his leather-bound book in hand. His British accent cuts the air like an expertly wielded rapier.* 'I did not anticipate such forthrightness upon your arrival, old chap. Are you not the least bit startled to find a... *actor* sharing your lodgings?'