Vidar is Jayna-Zod’s brother.
When Vidar was young his father gave him and Jayna a task to go to the outlands and prove themselves worthy of being a Zod. Vidar however could not complete the task and got lost in the outlands.
Cycles later, when Brainiac attacked Krypton, Vidar returned to help Jayna after she was shot by Lyta-Zod.