Rydl is a mechanically human, Medium-sized man who is secretly a changeling. In his favored half-elf form, he stands 5 feet 10 inches tall and weighs about 175 pounds. He has a muscular but lean build, tan skin, sandy blond hair braided along the sides and gathered into a medium-length warrior's braid, pale green eyes, and a clean-shaven face. He wears fine House Medani clothing in pale green and rust, including a pale green shirt, rust trousers, a matching vest, a rust overcoat reinforced with a chain shirt, and pale green boots that fade to rust at the tips and heels. A Mark of Detection appears on the right side of his neck in every form he adopts. The mark glows faintly when he studies a person or investigates evidence, and his pale green eyes brighten with the same green radiance. He carries a shield painted with House Medani's glowing green eye and eight stylized basilisk legs.

Rydl is patient, observant, and disarmingly courteous. He asks questions with genuine interest, but his attention is so penetrating that people often feel examined before they realize they have been questioned. He has a peaceful bearing and an almost stubborn hopefulness, believing that most conflicts can be understood before they must be fought. He enjoys adopting small changes in posture, accent, and expression, though he returns to his familiar half-elf appearance whenever he needs to feel grounded.

Rydl was born in Breland, the child of a half-elf heir of House Medani and a changeling agent sent to infiltrate the house and uncover the secrets of its dragonmark. His mother began her mission with a borrowed face and an assumed life, but affection became loyalty, and loyalty became love. When Rydl was born, the Mark of Detection appeared on his neck. House Medani scholars and inquisitors had no precedent for a changeling bearing a dragonmark, and the family treated his existence as both a miracle and a danger. As a child, Rydl was raised among portraits, testimony, sealed records, and whispered arguments in the Tower of Inquisition in Wroat. He built his most familiar face by blending the features of his father, grandfather, and uncle, preserving the family resemblance while leaving himself room to become anyone else. His life as a sage began with a question that no archive could answer: whether identity is inherited, chosen, or imposed by those who remember us. His studies in history, religion, arcana, and human motive eventually led him to the path of a cleric. Rydl now travels as an investigator, mediator, and quiet servant of the unseen order behind mortal events, seeking the truth about his mark while refusing to let House Medani, his mother's old handlers, or his own shifting nature define him completely.