NO
There are no legendary in dark cave in soulsilver that i know of, but i know alot of legendaries and I could list some of them if you want.
go throw diglits cave and when you get out,go down
Whilst a trainer in Challengers Cave does say there is a legendary Pokemon there, there is in fact no legendary Pokemon in the cave.
You can find it on certain days at the end of ICE Cave and many other legendary Pokemon not obtained in Heart Gold and SoulSilver.
No
No, there are no Legendary Pokémon in Challenger's Cave.
mewtwo
cerulean cave
mewtwo is in the cerulean cave but u hav to beat the elite four to get access to the cave. more help: the cerulean cave is in kanto in Pokemon soulsilver in the cerulean city... do u know the boy who says to u he came all the way here to get the legendary Pokemon well he is talking about mewtwo. and as u see theres a cave right over there where the boy is.
Cerulean Cave
Dark Cave
In cerulean cave