you can't find Uxie again if you have knocked out Uxie, unless u defeat the elite four again.
When you catch dialga/palkia or defeat them, you can catch azelf and uxie in the lakes.Mespirit will flee so you gotta get a poketech radar to track it down.
you catch him in lake valor
you catch raikou on the last gym leader in the kanto leaders and you catch uxie in vermillion city from
They will run away, and you have to find them in the wild and capture them.
yes uxie comes back to life after a while.
you can find uxie,azelf,and mespirit plz people say thank you to me ^_^
Uxie is in Lake Acuity after you catch Palkia. Go to Lake Verity first, go into Mesprit's cave, and the Professor will talk to you and you will be able to catch Azelf and Uxie. ~Lucario
the way you catch azelf mesprit and uxie.
Lake acuity cave.