Kekkaishi - Season 1 Episode 19 Attackers With White Feathers

An ayakashi disguised as a human sends three ayakashi to Karasumori and has then run around the place before allowing them to run amok in order to gather information. Yoshimori attacks one of them and it becomes angry and the observer eventually gives the signal. They gather together but Tokine destroys one of them making the other two angry. They combine and are empowered by Karasumori. Eventually Yoshimori and Tokine destroy the ayakashi and they send for clean-up help. But Madarao and Hakubi notice the human scent changing into an ayakashi scent and Yoshimori jumps to the roof to investigate finding the spy.