Witch Hat Atelier Vol. 6 (Kodansha, 2020)

Coco and her peers follow Olruggio and Luluci as they deftly ferry a wounded Qifrey to the underwater Great Hall where witches gather. To their surprise, Beldaruit of the Three Wise Ones awaits the young apprentices at the bottom of the ocean… And he's willing to offer another trial after Agott's and Richeh's was cut short. But the spells and tests of Beldaruit are as much a mystery to unfold as his past, and Coco may be the only one who can put the pieces together and close in on the startling truth…