if you mean seeing azelf without it going into your pokedex, 2 or 3. if you mean battling azelf withit going into your pokedex, twice. once when you first battle it in valor cave, and again when you have a rematch [after one week] if you defeated it the first time.
p.s. yes, you can battle legendaries (in dpt) twice.
Once unless you save before you battle him/her and you reset the game
YOU CAN CATCH HIM IN LAKE VALOR.BUT YOU HAVE TO CATCH YOUR REGION POKEMON.(PALKIA OR DIALGA).THEN YOU TRAVEL TO LAKE VALOR AND YOU WILL SEE A CAVERN.THEN YOU WILL SEE AZELF IN THE MIDDLE. JTROTTER1295
there is nothing you really need to do with azelf, uxie, and mersprit. you just need to see them to complete your pokedex.
Well, first if you set all three of them (Uxie Azelf Mespirit) free from team galacturd, you can find it again back in it's cave at lv. 50 i think..
lets see....heatran, giratina, uxie, mespirit, azelf, darkrai....yeah
uxie groudon mesprite azelf and dialga
you have to climb up mount Everest and then you see azelf and he pushes you down
Azelf is a legendary Pokemon.
you have to see it about 8,871 times
yes you must beat the elite 4
you go to all the caves in sinnoh (volar azelf acuity uxie and verity mespirt) and you will see them. battle them a try to catch them .But when you talk to Mespirt he will disappear .he will be roaming around sinnoh.
Take at least 18