Tokyo Ayakashi Street

Street child Hayato flies around the city every day to cover his hospitalized sister Himari's medical expenses. One day he runs into a boy he has never seen before graffitiing on a rooftop, and suddenly an "ayakashi"—a huge fantastical creature—appears! As it charges off towards the hospital, Hayato has no choice but to fight to protect his beloved little sister and city!

(Source: Kodansha, translated)