What does the doll provided by the duet theater mean?

The master elder brother duet is a traditional doll in China.

In the duet, only one character is represented, which may be because the duet sometimes has to be dressed as a doll, but at that time, you can't hold a real child and hold a doll as a representative. Their master elder brother (Western God) passed on backstage was active in the northeast until they turned over. Not many people know, so they don't know much about this worship.