Agents of STRIKE
Codename: The Negative Zone
Earth-N is not given a true number designation, because it wasn’t in the Council ledger we obtained and travelling there doesn’t use the same frequency method as travelling to other alternate Earths. Without getting into all the complex quantum mechanics, it is an Earth that exists outside the other Earths, and thus we don’t have a way to properly number it. Hence, Earth-N.
However, what is nonetheless true is that Earth-N is Earth. Or, at one point in its history, it was. Piercing the atmosphere with high-altitude probes allowed the Exploration Corps to conclude from stellar cartography that the Negative Zone is indeed an alternate Earth, occupying the same place in space with the same stars in the sky in more or less the same place as they should be.
However, it is not clear what events transpired in the Negative Zone that turned it into essentially a blasted, uninhabitable hellscape, where strange energies roil for reasons we do not comprehend.
Utmost safety precautions need to be taken in the Zone. On his initial journey, Dr. Reed Richards was unprepared for the bizarre energies of Earth-N and he and his team were radically altered at the molecular level after being bombarded with exotic radiation we have not been able to fully understand.
When personnel are sent into the Zone, they are properly shielded against this energy, as is our permanent facility on Earth-N, codenamed Wonderland.