This Model is to make mostly monocromatic artworks with white/black backgrounds.
Don't use prompts with colors, if you write "brown jacket, yellow eyes" it will follow the prompt and use colors, in my experience i've changed the prompts to "dark jacket, white eyes" and it worked great.
You can up the LoRA strength up to 1.2, this can fix some problems like the model making the skin with a pale color and not full white