A greek gods Soulmate

Ellara ugliano is the little half sister of percy jackson.
She comes with the thing that her brother a demigod is quite clear.
But she is still worried about him.
At 18, she visited him in his new apartment.
She stays there for a few days.
Everything seems perfect.She has a good time and quickly becomes friends with Annabeth.
But then the gods Show up and ask for percy.
Ellara comes along and accompanies him to the olympies. but mortals cannot actually enter Olympus.

so why can she?

Ellara would never have thought that she was meant for a god. His soulmate.

And her Brothers father, of all people.