Because I, the True Saint, was Banished, that Country is Done For! Vol. 7 (Because I, the True Saint, was Banished, that Country is Done For! (manga) #7)

After successfully aiding the fairies and establishing diplomatic ties with their kingdom, Eliane and Nigel return to Linchigham looking forward to some well-deserved rest. But Nigel wants to make one stop before the castle-a magical laboratory, where he wants to drop off the special water gifted to them by the fairies for analysis. Having long dreamed of becoming an apothecary, Eliane is completely fascinated by the lab and their production of potions. The lab's director offers to show her the ropes, and she jumps at the chance-but the combination of the fairies' water and her saintly magic yields some unexpected results…