Mackenzie the Beast is a orphan baby beast recently adopted into the LionKingHeartFantasy Films family.
She is found drifting into the river, laying inside of a small basket. While the gang are hanging out of the lake, Rae was swimming when she stumbled upon the basket. She first saw what's inside the basket and could not believe her own eyes. She rushes back to shore and shows everyone, including Benny what is inside the basket. When they see that the baby happens to be a beast, everyone stood in shock and amazement, stumbling upon another beast existing in life. They later uncover a small note that reads, "take care of Mackenzie", thus naming the baby Mackenzie.
Even though Mackenzie is a beast, she carries small human-like facial features, while only bearing tusks smaller than Benny's and saw smaller feet. As she grows, the tusks remain small, but her feet are getting slightly bigger. She inherits beautiful purple eyes and long dark brown hair.
In Benny, Leo, Johnny and Rae Meet the Great Beast, the team learns Mackenzie was born in Scotland and had a mother, Isla, who is human and a father Lazarus, who is a beast, thus making her half-beast. Her birth name is Mackenzie Isla Lazarus. Shortly after the events of The Great Beast, Benny has changed his status from Mackenzie's legal guardian to adoptive father.