Quote Originally Posted by Eidolon View Post
Let's take a look at Summoner:
Oh, you never actually fought Bahamut in 2.0? It's fine. YOU'RE TOTALLY ABLE TO CHANNEL HIS AETHER BECAUSE YOUR CHARACTER WAS AT CARTANEU.
The explanation changes slightly depending on if you're legacy or not:

Quote Originally Posted by Anonymoose View Post
In the LV58 Job Quest for SMN, Y'mhitra explains your interaction with Bahamut aether, and there's actually a flag that changes the explanation based on the experiences of your character.


Legacy
You were there at the Battle of Carteneau. You were there on the day of the Calamity when aether infused with the dragon's essence rained down upon the field.

Non-Legacy
On the day of the Calamity, the dragon vanished in an explosion so massive that his aether was carried to the far corners of Eorzea. You, among many others, have already been touched by his essence.