Aislin was born with the ability to influence the dreams of others. He often uses this power to help his friends, aiding them in understanding the problems they may be having in the waking world. He is also partially empathic, meaning he is sensitive to others' feelings.

Aislin has always been friends with Mirage; they were best friends when they were young and it was widely believed that they'd become mates when they got older. However, a game of hide-and-seek turned deadly for the filly, for when hiding behind an old, burnt-out tree stump, she injured herself and was infected with a virus long thought to be extinct. Aislin tried to help her to the then-Healer, Miach, but the virus affected her too quickly and she died that night. Feeling responsible, Aislin ran away and wasn't seen for a long time, though he helped her ghost keep one hoof in reality by visiting her in dreams. He was eventually set straight after Mirage's ghost was reunited with her grandmother.

Since realizing he wasn't responsible for Mirage's death, he's become an active member of the herd and has forgiven himself for what happened in the past.