This is a universe...
The Dutian Divine Domain is a universe.
The Angel Sanctuary is also a universe.
The Dark Abyss is likewise a universe.
No matter how numerous the Divine Race might be, they cannot prevent these Void Demons from entering.
Beneath the Supreme Demon Deities, in order to cross star systems, one basically relies on the Teleportation Gates within the major Star Cities to leap from place to place.
And now, in order to avoid Void contamination, the major Divine Clans have already consolidated their forces into shelters within their respective Divine Domains, with many Star Cities that were once bustling now sparsely populated.
Under such circumstances, it seems quite normal for beings like the Thousand-legged Centipede at the peak of the Supreme Demon Deities to break into the vicinity of the core area of the Dutian Divine Domain.