Crystal
"Thank you for telling me." Crystal said to them, "At the yearly meeting, why did you look at me?"

Eligos climbs up to the top of the rocky ledge, his dark-blue-scaled dragon feet clinging to the rocks and his tail swinging back and forth. He watches the landscape of the underworld carefully. Far, far away he can hear the voices of a girl (Crystal) and a powerful demon- Rivaros. He blinks, chains rattling a little, then scrambles back down into his field.

Rivaros

"I've never seen such a young apprentice, so I wondered why you were so special you broke expectations." As they walked past the gardens, he said to the workers. "Good job, you do good work."

Crystal
Crystal looked shocked at what they said and followed behind them, "I didn't know I was the youngest apprentice," Crystal said out loud.

(Yamii how are the angel chosen to be an apprentice exactly?)

she watches in silence as they talk her eyes scanning them

Eligon, from his perch on the rocks, listens in to what he can hear of their conversation. Whether he understands or not is a mystery.

she yawned with boredom sadly

(Out of the corner of her eye, she sees a dot of pale blue on the horizon. Does she pay attention to it?)

(basically if they have very strong magical abilities and understand it naturally well enough then they are chosen, so basically genetics.)

Rivaros

"You didn't know? The youngest one before you was 32 human years."

(lol maybe)