once your done with cerelean cave go to seven island and it will apear
mewtwo is in mystery cave :D
get every Pokemon in the game then go to mystery cave and catch it
Firered don't have a "solar cave"
In Altering Cave all you find are Zubats. The only way to get rare Pokemon from it is to use mystery gift but I think the event has passed so at this point it is pretty useless.
Zubat can be encountered in the Altering Cave. Originally, there was going to be a set Mystery Gifts distributed which could change which pokemon were encountered in the Altering Cave, but the Mystery Gifts were never distributed.
You can get Mewtwo in the Cerulean Cave.
You can't
in the land cave.
altering cave,
bartonvilleType your answer here...
Cerulean Cave
The only dark type Pokemon you can get in firered is murkrow which happens to be in lost cave on five island.