This is the character design book by Hyung-Tae Kim.
It contains characters from Magnacarta, Magnacarta the phantom of avalanche, The War of Genesis III Part.2, The War of Genesis III. At the back of the book are a few pages of line sketches.
The character designs are marvelous.
Included as a bonus is a how-to-paint process, although there are no captions.
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Here's the Amazon Japan buying guide for your reference.