In Veilstone city
Well, somewhere along the Galactic warehouse, you might be able to find it somewhere.
can find one in the team galactic warehouse or head quarters in Veilstone city When you have to free the three Pokemon they captured.
go tospear pillarafter rescuing the lake Pokemon before you get to dialga you must beat mars, Jupiter and the head of the team galactic the you will be able to battle him
All you have to do is go in the Galactic headquarters in diamond, pearl or platinum and fight Cyrus [The Boss that you face in the Galactic Building] and you have to beat him. When you beat him he will give you a Master ball and he will leave the Galactic building and head to Spear Pillar and will Summon Dialga. For more Information try to type on Youtube " How to get a Master Ball on Pokemon Diamond, pearl,or platinum " Bye!
You get a master ball either from your cheats if you have any or else you get a master ball from the boss of team galactic (cyrus when you beat him in head quarters).(This answer is for Pokemon Diamond and Pearl).
Head back to Jubilife City. Head North where Rowan and Dawn are. After battling Galactic Grunts go to the cave. HM6 Rock Smash is required. Get by man in the Oreburgh Gate.
the one that i know how to find is at the team galactic head quarters in veil stone u have to get the storage key first then go through the whole place and in the bosses chamber after you beat himhtre will be a master ball i don't now i only have oneYou only get one-per-whole game and that's it!
Azual is not a character in diamond there for you cannot find him however what you do after you beat Cyrus is go back and beat Saturn
If you are currently in the room where all of them are kept, it should be relatively easy. There should be a switch in front of the machine, as Juppiter (? or one of the other galactic leaders) will explain. Simply press "A" in front of the button and there you go! If you haven't gotten to that part yet. Make sure that Team Galactic captures all of them first at the three major lakes, then head to Veilstone city, and head north east to go to Galactic HQ
After you free misprit, azelf and uxie from team galactic head quarters if that is the painting your talking about
Next to the head quarters in veilestone he will get scared and run and drop the galactic key
you have to beat givoni at rocket head quarters