The Heaven Gate serves as the passage connecting to the Upper Realm, and the duty of the Boundary Guardian is to oversee it and prevent outlaws from breaking in.
Due to a lack of resources and rules, the Boundary Guardians were unwilling to guard the realm in person, as it would delay their cultivation, so they sent avatar projections instead. Over time, these became known as the Boundary Spirit Generals.
Being from the Upper Realm and demoted to the Lower Realm, they were naturally resentful and prone to bad tempers.
Chapter 2283