[ORAS] (SPOILER ALERT) Elite 4 isnt the end! With info with Rayquaza (spoiler too!)

[Joushou]

If you beat Deoxys without catching it the first time you can find it at the top of Sky Pillar after you beat the Elite 4 a second time. This way you only have to get Rayquaza, watch the cut scene, check the nature with a calculator, and reset as necessary. Then you can SR on the Deoxys until you get the nature/IVs you want separately. I just confirmed myself that Deoxys reappears.