Painting with the Dragon. Book 3. Danger from the Past and the Lotus Lantern

Excerpts from the book:
The remaining journey to the house where Ōi spent her childhood passed without incident. Having flown up, Shotaro landed, and the girls deftly jumped from his back to the ground.
“There really is a dark spell here,” the dragon said, looking around. “I think I also need to check out the inside of the house.”
“But how do you get inside?” the artist asked a reasonable question.
Her bewilderment was more than justified. After all, the dragon was a very large creature. Because of this, he simply cannot enter the houses of ordinary humans.
“Oh, I just recently learned to turn into a human!” he answered joyfully. And then he added in a sad voice: “But I didn’t think that this skill would be needed so quickly and for such a sad reason.”
Ōi and Satsuki looked at each other. The dragon concentrated. His face, which has extremely rich facial expressions, expressed great concentration. And then, after a few moments, the supernatural creature was engulfed in a silvery light. The radiance shrank before the girls’ eyes, as if Shotaro inside it was rapidly becoming smaller. Shrinking to the size of a human child, the glow began to take on the shape of a boy.
When the silver light went out, a boy about ten years old appeared before the eyes of the artist and the owner of the cosmetic shop. The girls, as soon as they saw him, were stunned on the spot. After all, this was Shotaro as a child! The same as they remembered him when he lived as a simple human! Except that now he seemed a little older.
“My human form looks the same as I did in my past life,” the boy commented on the obvious. “And this appearance corresponds to my current dragon age. The thing is, dragons grow differently than humans. Therefore, by human standards, I am now ten years old.”
Ōi and Satsuki, unable to contain their emotions, ran up to the boy and hugged him. He did not expect such a reaction, and asked in surprise:
“What's the matter with you? We've seen each other so many times! Even though I was in the form of a dragon.”
“But now you look so much like yourself as a child!” the girls exclaimed in one voice. “We didn’t think we’d see your old appearance again!”
“Probably because I became a dragon as a child, I don’t fully understand human feelings,” the boy decided to himself. “Apparently this is very important to them.”