According to Wang Yiyuan's explanation, Napa is a native of the Mingguang Realm, one of the top realms. However, he does not belong to the most powerful faction within his realm; his faction ranks only in the second tier there.
This is comparable to how, within the Defy God World where Duan Lingtian resides, a heavyweight Supreme God-level faction would rank just below the giant Supreme God-level factions across the various Realms of Gods...
Yet, even a faction ranking only in the second tier within the Mingguang Realm has a Supreme powerhouse ancestor guarding it!
Chapter 3986