The
Ainur were not permitted to dominate the Children of
Ilúvatar. That’s why the
Istari had the restrictions they did, and his decision to do otherwise was the precipitant cause of
Saruman’s fall to
evil.
Ulmo was in opposition to the rest of the
Valar in his counsels: he aided
Turgon and
Finrod, and after
Nirnaeth Arnoediad, sent
Tuor to
Gondolin. Then he helped Elwing and
Eärendil, bringing the embassy of
Elves and
Men to
Valinor. In this, he opposed his fellow Valar but pursued the will of
Eru.
In the Downfall of
Númenor, the fiendish plan of
Sauron was not only to turn the hearts of the
Númenóreans against the Valar, but to pit the Númenóreans against the Valar and
Maiar. While no force of Dúnedain could overcome a
Vala, Dúnedain could and did overcome Maiar, both
Balrogs (in Gondolin, in the early
tales) and in the defeat of Sauron in the
War of the Last Alliance. But because the Valar and Maiar were specifically prohibited from harming Elves or Men,
Manwë was unable to react to the invasion of Valinor: once
Ar-Pharazôn and his vanguard set foot upon the shores of Eldamar, Manwë’s only recourse was an appeal to Eru. Eru’s response was drastic and cataclysmic: Númenor was destroyed,
Arda was changed, and Valinor was removed from the Circles of the World, making it unaccessible to Men.
It is certainly possible that Ulmo was aware that the
Ruling Ring had fallen into
Anduin! That coupled with the rearising of Sauron in
the Third Age may well have been the impetus for the Valar sending the Istari to
Middle-earth with their aforementioned restrictions. But as the evil of
Morgoth spread through Middle-earth, even the
High Elves of the
First Age had difficulty hearing the voice of Ulmo in the waters: Ulmo himself mentions this in his appearance to Tuor.
As for Maiar and Umaiar left behind: After the
War of Wrath, Sauron first presented himself to
Eönwë, but faced with return to Valinor and long penance, he hid himself and fled into
the East. The
Balrog hid sometime during the War, and did not appear again for nearly two
ages of Middle-earth, when the unfortunate
Dwarves disturbed his hiding place. The nature of
Tom Bombadil is long debated, but I would venture to say that, intentional
enigmas aside, he and
Goldberry fit well into descriptions of Maiar; and that would well explain
Gandalf’s long visit he proposed as he left
Frodo and his companions on their return to
the Shire.
