By battling them in the wild, depending which generation your playing, if you can not do this then you must trade for them
A very legendary pokemon
there are no 3 legendary cats in Pokemon try 3 legendary dogsThe Pokemon company said that they were cats.
Because Arcanine is a legendary Pokemon. Check Arcanine's pokedex entries.
That means your file has corrupted By the way, they are the legendary cats, not dogs. The Pokemon Company revealed that Raikou is a tiger, Entei is a lion, and Suicune is a cheetah.
Yes it's even the last pokemon in the Unova pokedex.
Beat 49 gym leaders(Or NPC's)go to pokedex,search a legendary pokemon,click the map it's in(on bottom of the Legendary)and you catch it
rotom(legendary)
The legendary pokemon, Mew.
After Latios comes Kyogre, the legendary Pokemon for Sapphire Version.
No, you have to encounter them first.
Yes,I have this Pokedex book,it said Rotom was in the legendary section.
Mesprit Uxie azlef are the three other legendary Pokemon but not very good