In Pokémon Ruby, Cresselia cannot be found because it is not in the game's programming data. Cresselia was created for the 4th Generation of games; Pokémon Diamond and Pokémon Pearl which were for the Nintendo DS, Pokémon Ruby is a 3rd Generation game and therefore before the time that Cresselia was created as a Pokémon.
you find cresselia on full moon island
jirachi is on the first route but is very rare i dont know the others though.
You catch Cresselia
You can catch Cresselia on Marvelous Bridge, but you need the Lunar Wing, which you get in the Strange House.
you cant catch a man in Pokemon ruby
no you can catch a charizard in pokemon ruby you can get it as a kanto starter
you can't catch seviper on Pokemon ruby (Pokemon sapphire only)
you cant catch it anymore
no
::::::You can not get cresselia in Pokemon heartgold::::::::::::Yes you can!!! I have one! Well i have 2 because i got them from a trade but i sitll have them!:::: :Dno u dont you need to catch it in pearl and trade
Cresselia is found in Pokemon Platinum as a roaming Pokemon. After encountering Cresselia for the first time, one can follow its location by checking their Pokedex entry for the Pokemon. Cresselia can potentially appear in any patch of tall grass.
Sorry to say it but your games fake no such thing as Pokemon dwluge!