Venus is the twin planet to Earth that replaced the orbit of Mondas after it drifted away from Sol. Venus is covered in greenhouse gases and has a very hot surface, the hottest in the solar system. Venus was rumoured to contain some form of life that may have taken a gaseous form, however, it was proven by Humans that there is no life on the planet at all in 2021 PLF when the first Humans landed there.
The League's original name for Venus was S-003-12714, however, the name was officially changed by League officials who visisted Earth in 1898 PLF in disguise. Venus is named after a Roman God of beauty, love, fertility and prosperity, which is ironic since the planet itself has none of these qualities. All it has is dirt. It would have made sense to call Earth Venus and Venus Earth.