Secret realms
1) primary secret realms
Primary and intermediate level Pokémon inhabit this realms. Holds basic resources and normal Pokémon, these realms size is 2000 to 5000 km average. Humans can explore this level secret realm for long time without any side effects.Holds pokemon population in millions.
2) intermediate secret realms
These secret realms are inhabited by primary, intermediate and advanced pokemons, in rare cases pseudo elite pokémon, average size of 30000 to 50000 km. Humans can explore these realms continuously for significant time and holds tens of millions of pokemons.
3) advanced secret realms
These holds upto primary to elite level pokémon, holds various supernatural items and treasures, various rare pokémon and resources. Average size of pre pokémon era Europe continental size. These realms holds hundreds of millions of pokémon population. Humans can explore these realms for upto 5 years, if not they will be corroded by secret realms energy and can't exit without soecial circumstances.
4) Special advanced realms
These realms inhabited by champion level pokemons, holds various very rare and sought after ultimate and worldly treasures.humans can explore upto 3 years without any side effects. Average size of pre pokemon era European continent, in these realms only pokemon of specific attributes pokemons will be able to live and holds hundreds of millions of pokémon population.
For example, in dragon type special advanced secret only dragon type Pokémon will be able to live.
5) Top tier
These realms holds all types of pokémon , with numerous resources, rare pokémon, otherworldly treasures. Holds billions of pokémon population, God tier pokemon first found in these realms. Average size of top tier secret realms is pre pokemon era earth size, they are small planets on their own.
Humans can explore upto 1 year without safety measures or legendary and mythical pokemon help,if not they will be corroded by realms energy and can't exit.
RUINS
1) Primary
2) Intermediate
3) advanced
4) Top tier
They are small in size and typically don't hold pokemon in them. They holds technology and history of world, where pokemon are originally from, all technology and pokemon related research is from these ruins .
From these ruins humans learned about, God of pokémons " ARCEUS " , which current revered as Supreme God of Universe.