In jane eyre how are minor characters used to used to reveal more about major characters?

Two types of characters exist: Major characters and minor characters. Major characters are formed by authors, providing them with backstories. Minor characters on the other hand are just there "for the ride". They are known to impact the journey of major characters, but little in known about them. They basically form a support for major characters or function to challenge them. In Jane Eyre, minor characters are used to create learning events aimed at ensuring change and growth for major characters.