"Xiao Yu is a main character in the Japanese manga series ""Immortal Nanny Dad."" At the start of the series, he is a young boy who is taken care of by the protagonist, the immortal nanny dad. Xiao Yu is a good-natured child who is curious about the world around him. He has a kind heart and is always willing to help others.

Despite his young age, Xiao Yu is very intelligent and has an advanced understanding of technology. He is particularly interested in robotics and spends much of his free time programming and building machines. His skills often come in handy as he helps the immortal nanny dad with various tasks.

As Xiao Yu grows older, he becomes more independent and begins to take on greater responsibilities. He excels in school and earns top grades, showing his dedication to his academic pursuits. He also develops a deep interest in martial arts and begins to train under the guidance of the immortal nanny dad. With his hard work and determination, he soon becomes a skilled fighter in his own right.

Throughout the series, Xiao Yu's character undergoes significant growth and development. He learns valuable life lessons and gains a deeper understanding of the world around him. Despite facing many challenges and obstacles, he remains steadfast in his pursuit of personal growth and self-improvement.

Overall, Xiao Yu is a complex and well-developed character in ""Immortal Nanny Dad."" His intelligence, kindness, and determination make him a beloved character among fans of the manga series."