Children of the Whales manga volume 5 features story and art by Abi Umeda.

The people of the Mud Whale have fought off the forces of the Allied Empire—for now—and their only hope for continued survival is to find an ally from beyond the Sea of Sand. So when the bombastic Captain Rochalízo sails his ship alongside their island, Mayor Suou is ready and eager to befriend the stranger. But even if Rochalízo can offer asylum, they have no way to navigate the Mud Whale. That is, until the mysterious Aíma begins unlocking the Mud Whale’s secrets for Chakuro…