The Dark Time of Melkor

Oromae is preparing for the future in a way that the other Valar really are not at this point. They seem very passive, living for the present and enjoying the light of the trees. And we start to see that while the Valar are ignoring Middle Earth, Melkor is not. He continues to build his strength. It says here that he slept not, but watched and labored. During this time, the evil things that he had perverted walked abroad.