Walgis was a planet occupied by the thinking machine forces of Omnius prior to and during the Butlerian Jihad. It was also the site of the infamous First Hrethgir Rebellion. Ajax hunted down and killed every human living on the planet, regardless of their involvement in the uprising.

The planet, though possibly rendered uninhabitable to organic life after the First Hrethgir Rebellion, probably suffered further and heavier damage during the Great Purge by the Army of the Jihad.

Human slaves had survived however, discovered by philanthropist and activist Porce Bludd.

A Dune Universe Planet?

Sources: Dune: The Butlerian Jihad?, Dune: The Machine Crusade?, Dune: The Battle of Corrin?