A greatest power

It's a little strange story.I have some questions about it.
1.Why did Guan Yu appear as a money god in this book?
2.Why was every character a kid?
3.How did Sing think about what the greatest power is?

but its illustrations are cute and delicate.Everything in this book is lovely.Children are so imaginative that they can come up with so many ideas.I love the pratical one .They made many huge golden coins and a statue of Guan yu though I didn't think that Guan Yu is related with money,but he really had a red face in the China's history.