So the upgrade method more common among Outer Realm Demons is to cultivate the core of their own world. Once the core upgrades, they can choose a next-tier world and occupy it to achieve a level increase.
And Civilization Sacred Objects are one of the few items that can help the world core upgrade.
"From Xi Ya's information, the Outer Realm Demon I repelled should only be Guard Star Level. After leaving the planet, its strength is equivalent to a normal Peak Demigod."
"The Outer Realm Demon avatar in Peng City can fight against a Celestial King, it should at least be Basic Planet Level."
"And the Hunting Bow Celestial Star is a Level 5 Civilization Sacred Object."
"If obtained by the Outer Realm Demon, it should be able to completely refine it within ten thousand years. At that time, its core has a certain probability of advancing to Basic Planet Level..."
