PREVIOUSLY

Celann understood by reading the letter that it was over.
He wouldn’t see Luxia again.
Luxia had left again and she had disappeared without warning as usual.
Celann had a heartache at first, then he pulled himself together and remembered the moments he had spent with her since the beginning, from the vampire hunt until now in Goma Perdo Land.
Then he thanked her for everything she had for him and the others.

As for Luxia, no one has seen her since. Neither in Skyrim, nor on Akavir, nor at Fort Knox.
Maybe she was going to a province of Tamriel or she returned in Oblivion.
Maybe is she on the Moons or in another era?
No one knows except her and maybe Sanguine.

Some wondered if it was not an illusion, or played by the dardric princes and that Luxia was not real.
Others like Serana and Celann know that she really exists and even met her and traveled with her by her side.

One thing is certain, Luxia really exists. But no one will ever be where it is when she leaves.
It will remain a mystery until the end.