Silmarillion: Main characters (Book report)

[Glirdan]

Ok, so here's the deal. I'm reading the Silamarillion for my Grade 11 University level English class (independent study) and by the end of our March Break (which is about the second week of March) we need to have a book analysis done. Now, part of the criteria is to identify two main characters and about five secondary. I already have one main character picked out (Morgoth[if you think otherwise, please, let me know]). Now, what I need your help on is who do you think would be another main character? And which five should I choose as the secondary character's. My teacher wanted to discuss this with me later on but I said to myself "Why not ask the most knowledgeable Tolkien lover's I know?" So, if you don't mind, I'd really like to get your input on this subject. Thanks a million!