Viz has licensed the Splatoon manga spinoff for America:

VIZ Media is excited to announce the acquisition of the adorable SPLATOON manga series! This all ages title by Hinodeya Sankichi will debut late 2017, and is inspired by Nintendo’s third-person shooter video game, a breakout hit upon debut! In the manga, four Inklings who can transform between humanoid and squid-like forms get caught up in a Splatoon Turf War that launches them into amazing adventures!