I have a question about image generation

Why is it difficult for me to create images where two characters appear together? Why is it difficult for me to create images where two characters appear together? I specify how I want the image and after a lot of effort I manage to get both characters to appear, but Now the detail is what characteristics of character 1 are reflected in character 2. I mean that if one character is strong and another is thin, both characters come out thin or the character 2 has the face of character 1.

And I put a lot of specifications in the prompt and in the negative prompt but I still have those difficulties :/

I see that it is very easy for some and they just have to put the name of character 1 and character 2 and that's it.