Ragnar Vizsla was a Mandalorian male of the human species. He was a Foundling and the son of Paz Vizsla. In or after 9 ABY, he became a member of the Mandalorian sect known as the Children of the Watch, who were under the leadership of a woman called "the Armorer." Shortly after joining, he was bested in a training fight by Grogu, another foundling. Their training was interrupted when a large shriek-hawk captured Ragnar. The shriek-hawk devoured Ragnar before attempting to feed him to its young. Bo-Katan Kryze led a rescue mission, which included Paz Vizsla and Din Djarin, and they successfully retrieved Ragnar from the creature's nest the following day. Ragnar, together with the rest of his covert, relocated to the planet Nevarro.
Ragnar, along with his fellow covert members and Kryze's group, journeyed back to Mandalore. There, he successfully completed the ritual that had been interrupted by a lake monster in the waters near the Mandalorian covert's location. He was later present for the reactivation of the Great Forge, an event he celebrated with all the other Mandalorians.
The first appearance of Ragnar Vizsla was in "Chapter 17: The Apostate", the opening episode of The Mandalorian's third season, which premiered on March 1, 2023. Wesley Kimmel played the character, having previously portrayed a Tusken Raider child in The Book of Boba Fett. Jon Favreau, the executive producer, and the production team were impressed with Kimmel's performance and decided to give him a chance to show his face in a different Star Wars project. Kimmel found it challenging to keep his role a secret for an entire year. On March 1, 2023, he took to Instagram to announce his guest starring role in The Mandalorian. His surname was confirmed as Vizsla in "Embodying Vizsla," an article written by Jay Stobie and published in Star Wars Insider 223.