Ancient Pokémon were one of the special variants in Pokémon Vortex. These Pokémon had 25% more defense compared to other variants.
All of these Pokémon were made by staff of Pokémon Vortex. They cannot be found on the maps anymore.
In Version 2 of Pokémon Vortex, all Pokémon up to Generation V were obtainable in Ancient Variant.