The story
Studio Barcelona was founded on October 5, 2005, by Nobuyuki Suga following a split from Group TAC. Following unknown circumstances, the company technically went defunct and was recreated as Diomedéa by Makoto Kohara, who was previously an employee of Studio Barcelona, on November 28, 2007. The company's headquarters and much of the staff remained the same following the transition.
Between 2018 and 2020, Diomedéa collaborated with Studio Blanc under the brand name Ezóla. According to director Ryousuke Shibuya, Diomedéa was mainly in charge of the digital side (such as photography/compositing and digital coloring) while Studio Blanc's staff focused on the rest.
From Wikipedia’s article on Diomedéa, shared under CC BY-SA 4.0.4