He will be at level 75 and have the moves
You will find him in the Giant Chasm,
and he has a catch rate of three, and if you want to compare that to someone, other pokemon with a catch rate of 3 are.
Tornadus,Thunderus,Latios and Latias, and the legendary dogs.
and I don't know about him reappearing, but if you just save before you fight him, you should be ok.