u can catch a bagon at metor falls
train it up to lv 50 and get a powerful pokemon

There is a certain room where you can find it. but I can not give you exact directions but
I can tell you that you need a pokemon that knows surf and waterfall. surf is a little bit
easier to get than waterfall because you actually have to find it at a point pretty close
to facing the elite 4 But for some reason I cannot remember where to find it so you will
have to figure it out yourself unless you have them already

you go to the sky pillar, and you have to go over a bunch ofholes and if you fall in you
go down a bunch of floors and to the bottom.