The Blues Sea is a large sea found within the World of Eternal Sonata. The Fusion River carries water run off from Mt. Rock into this sea and ever since Forte began mining magitone at Mt. Rock to make mineral powder, the ecology of the sea has been deleteriously affected. The sea is sometimes traveled by pirate vessels.
The sea is located to the south of all major settlements in the World of Eternal Sonata and borders Ritardando.
Blues is a musical form and music genre that originated in African-American communities of the Deep South around the end of the 1800s, characterized by certain specific chord progressions. The usage of this naming is one of Eternal Sonata's many anachronisms.