In chapter 1027 we can see King’s face was drawn with screentone, a common visual trait for black character in manga.
But this could be another color like red, he’s a Lunarian after all.
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Which is kinda odd. In these 1000 chapters Oda always drawn all human character without screentone, despite some of them are black.
The same goes for Fishmen & Minks whom has colorful skin/fur.
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Oda has explained this before, applying screentone is pain in the ass (SBS 5). Hence why he stopped using it for character design.
Also, just using black & white will gave him easy design contrast.
So this is my thought on why he’s using it on King:
1. Visual indicator for Lunarian
Whatever King’s color is, fullbody or partially, we the “readers” will identified/associated the Lunarian with screentone.
Which mean this is a set up for more Lunarian in the future chapter.
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2. Visual indicator for his power/condition/emotion
Oda never uses screentone for character design (except for Shanks)
But he still used it for some of their power/ability, mainly for visual contrast.
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This could be:
– He can turn it on/off like Haki;
– Some kind of condition/side effect Lunarians have;
– Emotion/anger based or something;
Whatever it was, we can see the difference between normal King and black/red King visually.
– Sasuke styled
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Regardless, one thing for sure. If Oda broke his easy design pattern after 1000 chapters in the story, there has to be some purpose on why he’s using screentone on King.
*Theory by kapteninsting