The Noah Church, as can be inferred from its name, is the church that worships the Eternal World Tree—Noah and is the only orthodox state religion of the Shining Country.
With a population of sixty million, most cities with a population exceeding 50,000 have a branch of the Noah Church. Sometimes, the bishop's status within these branches can even surpass that of the local City Owner.
Though Luca's strength hasn't reached Tier Five, by virtue of his bishop-level priesthood and prayers to the Noah Divine Tree, he can use Tier Five Divine Skills within the territory of the Shining Country.
And the root attribute of the Noah Divine Tree is "light and judgment."
When light and judgment descend, all sins cannot hide; therefore, even though he knew from the divine oracle of the Noah Divine Tree that the Fallen Divine Tree here possessed great strength, he was quite confident.
As long as he had enough time to use Divine Skills, everything would turn out fine.