Daughter of Boba Fett and Sintas, a fellow bounty hunter who died when Ailyn was a young child
Ailyn felt bitter towards her bounty hunter father for a long time and spent many of her early years hunting him down. At one point Ailyn thought she had succeeded in killing her father but the man she murdered was actually one of Jango Fett's clones from the Clone Wars named Spar. Ailyn took the armor of this "false" Fett and actually pretended to be the infamous bounty hunter for some time.
Eventually though, father and daughter would meet one another again, but by this time the bitterness for her father had subsided and they were able to join one another in re-establishing the Mandalorians presence in the Galaxy.