Literature
How to Design complex characters using core belief
A character is basically formed by three things: Personality, Beliefs, History
After designing the character's story and personality, what will help them stay in character is designing the layers of their core beliefs.
The key thing is, these core beliefs are never, ever spoken by the character themselves. They just behave in this belief like it's normal and not even think it's there.
Of course you can still choose to have them say it, they will just be a simpler open book type character. Or say it partially hiding its true statement, you can also use a character's core belief statement to make it a story statement if you see fit.
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