Mithril Lid Pod is a water fairy born from a drop of water in the giant Lake Loess of northern Highland. This origin grants him the ability to generate and manipulate small amounts of water. He possesses blue eyes and silver hair with a light blue accent, wearing his torn wing as a scarf around his neck. His attire typically consists of a light blue coat over a white shirt, gray pants, leather boots, and gloves.

Rescued by Anne Halford while being beaten by his master for attempting to steal back his wing, he refuses to thank her due to his distrust of humans. Despite this initial refusal, he later seeks Anne out to repay the debt and chooses to travel with her. He insists others address him by his full name.

His personality is stubborn, grumpy, sensitive, reliable, and energetic. He is notably talkative, contrasting with companions like Challe. During travels, he faces false accusations of stealing Anne's silver sugar, later revealed as a setup by Jonas's fairy, Cathy. In retaliation, he consumes Jonas's stolen silver sugar, causing Jonas public embarrassment.

Mithril Lid Pod demonstrates loyalty and perceptiveness, supporting Anne's evolving relationship with Challe and facilitating their bond. Beyond water manipulation, he exhibits resourcefulness, such as organizing a ghost hunt at Holly Leaf Castle to preserve peace, leading to the capture of a ghost connected to the castle's history. He provides comic relief and undertakes significant actions, like noticing anomalies in Anne's silver sugar that aid in resolving plot conflicts. His backstory as a labor fairy and the loss of his wing underscore themes of freedom and dignity, aligning with his journey toward self-determination alongside Anne and her companions.