The Valar

[Elrian]

Thus it came to pass that of the Ainur some abode still with Iluvatar beyond the confines of the World; but others and among them "many of the greatest and most fair", took leave of Iluvatar and descended into it. But this condition Iluvatar made, or it is the necessity of their love, that their power should thenceforth be contained and bounded in the World, to be within it for ever, until it is complete, so that they are it's life and it is theirs. And therefore they are named the Valar, the Powers of the World.

According to this they were many of the greatest. If the Encyclopedia of Arda is incorrect as you say, maybe you should contact them and point out their mistake. they'd probably want to correct that.
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