Allusion is illustrated through the entire poem.
Allusion is an brief and indirect reference to a place, person, thing, or idea of historical, culture, political significance, or literary.
Furthermore allusion doesn't describe in detail the person or thing it refers to.
Hope I helped ;)
Enjambment - the sentences do not finish with the end of the line.
Simile - "like a slackened drum"
Maybe even hyperbole, since it is an exaggeration.
Well, some of the main characters are Harry, Ron, Hermione, Dumbledore, and Voldemort. But some minor characters that really help contribute to the story are the entire Weasley family, Remus Lupin, Sirius Black, and Snape.