Confused about how to catch all three legendary Pokemon: Thundurus, Landorus, and Tornadus?

Question

I know where I can get the three because thats already been asked on where to find them etc but the question is how can I catch all three of them? I've been working on catching Tornadus but the problem is he wont stay in any of the pokeballs (ultra balls, timer balls etc) and I only have ONE master ball cause well thats all you get in the game any way is one.

And sure only catching one of the three is great but I want to catch all three of them so I can have the complete set of the three. what kind of strategy can I use? I've gotten Tornadus down to barely any HP left and he's paralyzed but I still cant capture him and I wanna avoid using the master ball if I can. I know you can use mean look to keep them from running away so I've been doing that but it doesn't help cause after at least three or four turns he flees.

Answer 1

if its night you could try a dusk ball or a quick ball

Answer 2

Have a Fast Pokemon that can use Sleep Moves like Spore on Thundurus.Then use Mean Look or Block and battle it until he has a little HP.use many Ultra Balls until you catch it.
For Tornadus the same.Use Mean Look or Block on it.Careful, don't use sleep moves if it is already paralyzed.Then use ultra balls until you catch him.Do NOT,I repeat, Do NOT use your Master Ball.Save it for another time.If I find more ways i'll edit.

Comments

If you want to its possible to use a quick ball if its a roaming legendary (its a roaming legend right?)