The Evil Dragon's Death Note

For an evil dragon, being a villain is the most promising career. Kidnap every beautiful and kind princess you see, rob any treasure worth a fortune you find, and if you come across a hero living a happy life, give him a couple of kicks before running off. But the dragon Neros is an exception. He isn't troubled by the job, has even befriended a human, and received a precious gift from them. "What kind of gift? Mind showing me?" "A powerful book of magic notes. Here." "Remember to pray devoutly when you wake up, return home and get married as soon as the war is over, challenge the powdered bald guy to a duel once you become a god, and be sure to kill any rabbits named Daisy and their lookalikes you find along the way... Neros, what did that human friend of yours do again?" "He was the dragon-slaying hero summoned by the king. Why?"