Here Pengolodh adds a long note on the use of hröar（body） by the Valar. In brief he says that though in origin a "self-arraying", it may tend to approach the state of "incarnation", especially with the lesser members of that order (the Maiar). "It is said that the longer and the more the same hröa is used, the greater is the bond of habit, and the less do the 'self-arrayed' desire to leave it. As raiment may soon cease to be adornment, and becomes (as is said in the tongues of both Elves and Men) a 'habit', a customary garb. Or if among Elves and Men it be worn to mitigate heat or cold, it soon makes the clad body less able to endure these things when naked". Pengolodh also cites the opinion that if a "spirit" (that is, one of those not embodied by creation) uses a hröa for the furtherance of its personal purposes, or (still more) for the enjoyment of bodily faculties, it finds it increasingly difficult to operate without the hröa. The things that are most binding are those that in the Incarnate have to do with the life of the hröa itself, its sustenance and its propagation. Thus eating and drinking are binding, but not the delight in beauty of sound or form. Most binding is begetting or conceiving. （Ósanwe-kenta）
The great Valar do not do these things: they beget not, neither do they eat and drink..."We do not know the axani (laws, rules, as primarily proceeding from Eru) that were laid down upon the Valar with particular reference to their state, but it seems clear that there was no axan against these things. Nonetheless it appears to be an axan, or maybe necessary consequence, that if they are done, then the spirit must dwell in the body that it used, and be under the same necessities as the Incarnate. The only case that is known in the histories of the Eldar is that of Melian who became the spouse of King Elu-thingol. This certainly was not evil or against the will of Eru, and though it led to sorrow, both Elves and Men were enriched. （Ósanwe-kenta）
Melian alone of all those spirits assumed a bodily form, not only as a raiment but as a permanent habitation in form and powers like to the bodies of the Elves. This she did for love of Elwe; and it was permitted, no doubt because this union had already been foreseen in the beginning of things, and was woven into the Amarth of the world...(Peoples of Middle Earth)
... in that union she became bound by the chain and trammels of the flesh of Arda. In that form she bore to him Lúthien Tinúviel; and in that form she gained a power over the substance of Arda... (The Silmarillion)
如果理解为“超越阿尔达物质的力量”，那么，阿尔达的物质，无论它多硬都有一点共同的——能被破坏（指物理损坏）。“超越”的意思是这种力量无法被物理破坏？这样的力量倒是存在，mind的。美丽安环带那种“none thereafter could pass against her will or the will of King Thingol”的作用，倒是跟“Nothing can penetrate the barrier of Unwill”有异曲同工之处，直接用“拒绝”（mind closed）把对方“墙”了。意识上的“墙”，除了伊露维塔是无法强行破坏的，米尔寇试过，失败——“To her(Melian) often his(Morgoth) thought reached out, and there was foiled.武力硬闯也试过，不过基本每次到边境就被切掉了，“Doriath he knew, but could not enter yet.”但这应该不能算环带的作用。唯二进来的两个不是天机就是神谕或者是主线剧情强制通过……我没找到环带对强行武力闯入者的作用的例子，对此我深表遗憾【喂】
美莲太太您可以出书了，《Fifty Shades of Grey·魔法森林版》，阿门洲限量200本【你很烦啊！
Thus, as 'Morgoth', when Melkor was confronted by the existence of other inhabitants of Arda, with other wills and intelligences, he was enraged by the mere fact of their existence, his only notion of dealing with them was by physical force, or the fear of it. His sole ultimate object was their destruction. (Myths Transformed, HoME 10）
Melkor alone of the Great became at last bound to a bodily form; but that was because of the use that he made of this in his purpose to become Lord of the Incarnate, and of the great evils that he did in the visible body. Also he had dissipated his native powers in the control of his agents and servants, so that he became in the end, in himself and without their support, a weakened thing, consumed by hate and unable to restore himself from the state into which he had fallen.
Melkor could not 'beget', or have any spouse (though he attempted to ravish Arien, this was to destroy and distain her, not to beget fiery offspring).