Appearance
Although unshowed, Atrions claimed the Zeons shared their physical appearance (humanoid, indeed), despite having a different attire.
History
Prior to the Atrion-Zeon War, the natives of Zeos had a relatively good relationship with their neighbours on the planet Atrios. This eventually deteriorated, leading to war between the two planets. It later turned out that the planet was totally depopulated, for unspecified reasons. (TV: The Armageddon Factor)
- The Atrians could have unknowingly succeeded in wiping out the Zeons at some point during the war, the Shadow could have deliberately wiped out the population via unknown means, or the Zeons could have abandoned their planet.