Natsume's Book of Friends: The Waking Rock and the Strange Visitor

Ishiokoshi: Natsume meets a small "youkai," a sprit, named Mitsumi in the woods.vIt is said that he is entrusted with the task of "Ishiokoshi," which is to wake up the divine youkai "Iwatetsu." However, for the reward of Sake, Nyanko-sensei and the youkai begin plotting to steal the task.vMitsumi weighs on Natsume's mind, so he decides to help Mitsumi with his task. Ayashiki Raihou-sha: A mysterious visitor appears in front of Tanuma. Nearly every day, the visitor visits Tanuma, talks to him a little, and leaves. Natsume is worried for Tanuma when he learns that the visitor is a youkai. but Tanuma has come to enjoy these interactions.. It seems like the youkai means no harm, but Tanuma's physical health gradually starts to deteriorate.