Grandpa just saw a dragon. Which novel is it?

"Grandpa, I just saw a dragon" comes from the novel Dragon, which means "Grandpa, I just saw a dragon". Dragon is a series of novels written by writer Jiangnan, which was later adapted into a comic book. In comics, Ricardo Miru is the protagonist. He grew up with his grandfather, who was a member of the dragon slayer. Once, Ricardo Milu saw a creature suspected of being a dragon in the deep sea. So I asked my grandfather for help. Ricardo Miru's grandfather said this: "Grandpa, I just saw a dragon." . In the novels and cartoons of "Dragon", the line "Grandpa, I just saw a dragon" appears many times. Whenever Ricardo Miru encounters a dragon-related situation, he will ask his grandfather for help.