Is this sentence okay
Could I get some tips with my yr 11 Romeo and Juliet essay?
Their houses are sworn enemies; their hate deriving from an “ancient grudge” (prologue, line 3) which has emblazoned into “new mutiny” (prologue, line 3).
Is emblazoned used correctly
The essay topic is: Who is most responsible for the deaths af R and J
Concerning your essay about who is most responsible for the deaths of the two young lovers in Shakespeare's Romeo and Juliet, I suggest that you don't need to change your topic. While it's possible a consensus might exist that Romeo and Juliet and their impulsiveness carry the most responsibility for their downfalls, one can certainly argue for the predominance of other causes. Multiple layers of meaning and ambiguity exist, so there certainly is no problem making an argument other than the lovers' impulsiveness.
Concerning the sentence you ask about, is it your thesis? Or a topic sentence? It would help us to know. If it's a thesis you would have some work to do. I'll assume it's not.
If you want to keep punctuation similar to what you have, I'd suggest the following:
Their houses are sworn enemies: their hatred of one another derived from an "ancient grudge" that has recently flared up into "new mutiny."
You should, of course, have references in parentheses after the quotes, but I suggest you avoid the awkward references here (The Prologue, etc., is cumbersome), by simply indicating to the reader ahead of time that that's where you are quoting from.
In the play's prologue, their houses are revealed to be sworn enemies: their hatred of one another derived from an "ancient grudge" that has recently flared up into "new mutiny."
If the passive voice of "are revealed to be" bothers you, you can play around with it and eliminate it.
If you do not have a previous sentence with an antecedent for their, you will need to change this pronoun to a noun since all pronouns must have antecedents. Then, you may wish something like this:
The Montague and Capulet houses are sworn to enmity as their hate, derived from an "ancient grudge," has flared into a "new mutiny."
Is this the topic sentence? If so, you may wish to modify it to better fit the essay topic. The real villain in Romeo and Juliet is the impulsiveness of the main characters is most responsible for the tragic deaths of the two "star-crossed" lovers. This impulsiveness is exhibited by not only Romeo and Juliet, but Tybalt and Mercutio, the Nurse, Friar Laurence, and Lord and Lady Capulet.
For details on their impulsiveness see the link below.
In answer to your first question, no, "emblazoned" is not used correctly. It means to inscribe, to sort of decorate some kind of surface with something. So you can have a shield "emblazoned" with a coat of arms.
I think you could just say "blazed" or "blazed up."
As for your essay in general, I don't know if you have a specific question or not. I think there are so many people you could blame for these deaths. I guess I would so with Lord Capulet for being so nasty when Juliet didn't want to marry Paris. After that, I can't imagine Juliet telling her dad what was up with her and Romeo.