Inertia

Inertia is a well-mannered girl who first appears in the hospital that Kino is requested to visit, reading a letter. She is described in the novel as a girl with pure white hair, long blond hair that touches the bed when in a sitting position, blue eyes, and a thin face. Instead of a hospital gown, she wears pajamas with a red and blue tomato pattern, with a pink cardigan on top.

She's in correspondence with a boy named Rogue who lives in an undeveloped land and wishes to see him when she recovers from her illness. She writes to him every month.

(Source: Kino's Journey Wiki, edited)