>>211603542Eru isn’t brought up by name, either, but he’s very much ‘the One’ like how God is ‘the One’.
Eru is only directly mentioned twice, both times in Appendix A of RotK, and both times only as "the One". The first time is in the section on the history of Numenor:
— At length Ar-Pharazôn listened to this counsel, for he felt the waning of his days and was besotted by the fear of Death. He prepared then the greatest armament that the world had seen, and when all was ready he sounded his trumpets and set sail; and he broke the Ban of the Valar, going up with war to wrest everlasting life from the Lords of the West. But when Ar-Pharazôn set foot upon the shores of Aman the Blessed, the Valar laid down their Guardianship and called upon the One, and the world was changed. Númenor was thrown down and swallowed in the Sea, and the Undying Lands were removed for ever from the circles of the world. So ended the glory of Númenor.
The second is when Arwen mentions him in the Tale of Aragorn and Arwen:
— “Nay, dear lord,” she said, “that choice is long over. There is now no ship that would bear me hence, and I must indeed abide the Doom of Men, whether I will or I nill: the loss and the silence. But I say to you, King of the Númenóreans, not till now have I understood the tale of your people and their fall. As wicked fools I scorned them, but I pity them at last. For if this is indeed, as the Eldar say, the gift of the One to Men, it is bitter to receive.”
This is all very Christian, since the Name of God is sometimes just really a name at all, but rather a descriptor.