Main theme of my comic1:
Hope.
The main theme for my novel Shackles would be:
Duty to the country over personal interest, and breaking the shackles of your past.
For my recently posted zombie story, it would be:
The destructive nature of humans, and finding meaning in life.
Though I think theme's isn't about morals to be honest, I have some young artist tell me the same and I always tell the thing. Would you speak without having something to say? Without having a goal in mind. Even a greeting has a goal.
Writing is a conversation, you, the writer, is conversing with the reader. Why should the reader "listen" to you if you haven't anything to say?
And it isn't just Disney and pixar movies who has themes, the Lord of the Ring's also had a theme. Even the smallest person can make a change. While the hobbit was about greed. Star wars is about hope and growing up. Even writers like Kafka has themes, though theirs are often philosophical.
Well, I find that most writer saying that they don't want to convey a message often do so just unconsciously. It's one of those thing when people say that they are not political because they don't vote but not voting is a political statement. It's saying that you don't trust in the political system or politicians 
Sounds like the main theme of your two books is finding yourself. Finding out what is important and what to fight for. Or do you feel like the two books have different goals? I often switches between books. My first Primalcraft is about stop running and facing who you are, while the second book will be to stand strong and hold on to who you are. It's an evolution of the first theme. What happens after you stop running, so to speak.
Sounds like both your books has a lot of personal sacrifice as theme. I see a pattern. Could it possibly be that you strongly believe that people should help other before helping themselves?
I guess the first book is more of this:
While the other one... still doesn't seem right 
Maybe finding a sense of belongings while also finding a way home?
Though I'm really not sure what the themes really are, at the very least, I know what the characters want throughout the story 
That's an interesting point you bring up but it's quite the opposite actually! I believe people should help themselves first before they can help others. 
I agree though that the first book involves the Empress Dowager sacrificing her happiness for the sake of her country and people. But her strong desire for that power stemmed partly from revenge, and it also involved her killing her own baby (among dozens of other casualties). So I guess you could say it's kind of a gray line for her maybe? 
For the zombie story, I don't see much of sacrifice. It's more about the play between the frailty and strength of humankind.
Well, often the theme are intertwined with the main characters since it's their journey the reader follows, so if you know what your character wants then you most likely have a theme even though you haven't really thought about it 
Ah, a twist. Normally a zombie story is about self sacrifice and working together to be able to survive. Betrayal and selfishness is often common in those stories because they act as a contrast to the unselfish main character who survives in the end while the selfish one dies. Often alone.
Yikes, the Empress sounds a lot like the historical Chinese Empresses. Is the story perhaps inspired by Empress Lu Shi or Empress Wu Zetian?
I think that tend to happen when you go on too long in a series. It's hard to keep the same theme in a story or comics (in your case) for over 200 chapters, or pages. Sooner or later, you will have to change or evolve what the story is about to make it interested. That is one of the difference between physical comics/novels compared to online ones that seem to never be finished. Theme is often connected to the end goal but if your story doesn't have an end... 
If i had to say a theme for mine I'd probably pick something between coming to terms with who you are and accepting the past and moving forward.
I don't necessarily focus on particular themes when writing, but I guess they eventually crop up once the story has matured as I near its completion.
Usually my priority is figuring my character arcs first and foremost and themes come in tow with that.
So for my novel I suppose its themes are dealing with loss and taking chances.
Creating conflicts can passively develop themes, which is why most stories have several. For me, I usually write by the sat of my pants so I don't get bored of the story. If I know what's going to happen in the story, it stops being fun to write. That's why I say don't care about theming in my stories.
We all have our style of writing
I personally prefer to understand what my message is before I start to read and I don't get bored writing my story. That has never been an issue for me. My issue is that I cannot write fast enough for all the things I want to add to my story. Ah, the limitation of being human 
Honestly, I more so have an idea for the story rather than for the theme. If a theme comes about from someone's interpretation, then I'm glad they found it. However, if I were to pinpoint a central theme (or rather message) to the story I am currently writing, it would be that you should not be afraid to do what you think is right, even if you have many detractors. Granted, I personally just see it as a fun story about a club centered on apocalypse survival, but you may be able to interpret such a theme from the "star of the story."
The main theme of my story Wolfie is learning to forgive yourself when you think what you have done is unforgivable.
From there it branches out and Annette has to learn to deal with reality while also dealing with the ghost of her idol Mozart.
I thought the idea of forgiving oneself was really interesting to explore because I feel it's one of the hardest things for people to do.
