The Art of Splatoon
From Inkipedia, the Splatoon wiki
The Splatoon Ikasu Artbook (スプラトゥーン イカすアートブック Supuratūn Ikasu Ātobukku) is a book of official art from Splatoon, released in Japan on October 10, 2015. It contains over 300 pages of concept art, character designs, and other topics from the game.[1]
The book is published by Kadokawa Dwango and is estimated to be sold for 2,400 yen.[2] It is currently only available in Japan, and there has so far been no information on an international release.