[Mithadan]

Melkor repudiated all axani [rules]. He would also abolish (for himself) all únati {things impossible to do] if he could. Indeed in his beginning and the days of his great might the most ruinous of his violences came from his endeavour so to order Eä that there were no limits or obstacles to his will. But this he could not do. The únati remained, a perpetual reminder of the existence of Eru and His invincibility, a reminder also of the co-existence with himself of other beings (equal in descent if not in power) impregnable by force. From this proceeds his unceasing and unappeasable rage.

The quote is from Osanwe-kenta and the bracketed materials are translations (more or less from elsewhere in the article. To say Morgoth's "elements" were heat and cold is an oversimplification (just as it is to say Manwe's element was the air). Morgoth sought to break all moral and physical rules out of his own selfishness and egoism.