Can't find Damien and Nora after Damien's quest

Where are they supposed to be? I caught Lugia and Kyogre… but I am looking for them cause Damien should give me Shaymin and I read there’s a Nora’s quest and she gives Celebi after that quest.

They show up after the second time you beat E4.

Ah okay, so after catching Lugia, Kyogre, Arceus… apart from other quests like catching Mewtwo, etc. The storyline which comes next would be beating the E4 again?