themes are v v important in your book. in fact, its one of THE things you need to have

so, what is a theme?

we talked about allegories earlier...but its not exactly a theme. it goes hand in hand with a theme (animal farm was an allegory of communism in russia, but one of the themes was a corrupt government)

a theme is the central message of your story. why you wrote it. what you intend for your audience to take away

themes are represented all throughout your story. your theme lives (and is supported) by your plot, your characters, everything.

one of the big themes ive put in necromancer is parenting, and how parents (aka the nurture) are incredibly important in the development of a child.

therefore, i have victor and his parents. they struggle at times, but for the most part, they care for victor and raise him with love. victor finds support and comfort with his parents.

on the flipside, i also have asher and pilate serving as foil. asher is a horrible father and abuses and neglects pilate. as a result, pilate's mental state was heavily affected and he is unable to properly display affection (as he was never shown any).

i also have seraph's story: the kid completely fell apart due to the oppressive and limiting parenting style of celeste.

another example of an overlying theme: in harry potter, the power of love is a major theme. harry was protected from voldemort's spell by the sheer power of his mother's love. voldemort could not feel love, therefore he was weaker than harry and was defeated. love is more power than magic.

steven universe also has a theme of non-violence; that peaceful resolutions work better than violent ones. the big example of this was in the cluster episode: peridot wants to kill it, but steven insists on actually trying to talk to it. he gets through to it and succeeds, conflict resolved.

a theme doesn't have to be overtly preachy. subtly using the same plot frequently can establish your theme (how many episodes of su has a 'gems wanna kill/fight something but steven goes the peaceful approach and succeeds' plot) but it does need to be there. your audience should be like "yeah, this thing keeps popping up, it means [x]"

using the opposite side of your theme is good too. so, since love is the most powerful element of all, a person that cannot love or hates love will naturally be the antagonist. bad parents will prove your parenting theme. violent brutish villains will prove your nonviolence theme as the right way to go.

COMMON THEMES:

-power of love
   ¤love overcomes anything

-death
   ¤death is nothing to be afraid of, dont fear the reaper
   ¤death is a natural thing of life

-immorality
   ¤immortality would suck
   ¤eternal life would be rad

-human nature
   ¤humans, by nature, suck
   ¤humans, by nature, are good

-government and power
   ¤power corrupts
   ¤the government is evil
   ¤with great power comes great responsibility
   ¤ruling through fear, rather its right or wrong
   ¤suppression of the people

-science
   ¤science is evil, technology is evil, advancing society/trying to outdo or play God is evil ( the movement of 'romanticism')
   ¤science is necessary, science is better/trumps than religion

-religion
   ¤religion is evil
   ¤religion is good

-ethics
   ¤pacifism
   ¤violence really is the answer
   ¤accepting others
   ¤sacrifices
   ¤selflessness vs selfishness

-human relations
   ¤parenting
   ¤nature vs nurture
   ¤marriage
   ¤how relationships aren't what they seen
   ¤beauty is skin deep

and many more. the themes are endless. in fact, pick an ideology you are passionate about (personally, parent and child relations are important to me, so i used that for nfh) and base your story around it. 

ask yourself: what do you want to teach the world?