Uh. Overcoming your fears and becoming true to yourself? I don't even know.
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.
All my stories are flexible, with theme mostly revolving around social isolation and trauma and how people at two far ends of a spectrum interact. It's more about how people interact than anything else, how social interaction or lack of it can corrupt someone and easily cripple their mental state.
The main theme of my novel is “FRIENDS stick TOGETHER”.
Also, “that's what friends are for”! Google it to find the 80's hit.
Comic writer here (sorta, not really..)
My comic would have family and trust as the main themes, but they kinda came up unintentionally? I didn't write it from the get-go with the idea of basing the plot off of them. It's only when I stepped back after a while that I was like "Huh, I guess if you had to put it a certain way.. those ideas would sum it up pretty well."
I wanted to base it off of teamwork, but the story kinda gravitated towards one character's development. It's a duo, but it's basically the story of one of them being supported by the other to the point of changing her. Which I guess goes back to teamwork, but as an unofficial secondary theme lol
Yup, you could say that! 
Morality is such a grey line, and in survival situations, it doesn't pay to be kind.
Oh yes some of the historical facts are taken from Empress Wu Zetian! 
I'm happy that you noticed that!
I would say the main theme of Inheritance is identity and how all the characters feel trapped by some unavoidable, inescapable biological function of their identity whether it be genes, sex, species, etc. There's also a lot of inner weaknesses for the characters to overcome.
Interesting, would you say it's more character driven or is it more characters against society? (which is often a theme when using identity in stories, such as rasism and homophobia)
