Konno Risa manga
From Elision-Scans: One day, Unohana unexpectedly meets two brothers — and they both happen to be demons. Nobody can see them except for Unohana, a schoolgirl who can see what nobody else can see. But when she is attacked by the spirit of a black dog, even more strange forces are awoken.
- Chap 1 Demons Captivated by a Flower (4 years ago)
Haruru Shirosaki, a girl whose father is a director, is always busy. Her best friend is Mami. She visits a girl's school across the road from a boy's school. One day she sees a boy in the window of the boy's school. When she comes home from school the boy she had seen earlier is there saying he will become her butler? Is this just a dream?