Here is how Princess Yuna discovered the Indominus Rex and became a tamer to the animals in Genesis World.
At the I-Rex paddock, Moon Dancer is showing Yuna and her friends around Genesis World.
Moon Dancer: This is the Paddock of the very first dinosaur hybrid called. Indominus Rex.
Moon Shoes: You mean the one from Jurassic World, Mom?
Moon Dancer: (chuckles) That's right, Moon Shoe.
Armor Bride: The Indominus Rex?
Sweetie Heart: What is this thing made of?
Moon Dancer: She is half T-Rex, the rest is Velociraptor, Carnotaurus, Giganotosaurus, Majungasaurus, Rugops and Therizinosaurus and the two modern animals, The Cuttlefish and the Tree Frog.
Princess Yuna: I remembered that!
Snowdrop: Me too.
Princess Yuna: The servants of Chernabog had a couple of Indominus Rex of their own while Sméagol, Skyla, Snowdrop, Twila and I are getting close to Armageddor.
Nyx: What's her name?
Moon Dancer: We've named her "Dawn".
Moon Dancer: It was the name that was given by Radcliffe while creating his own theme park after she hatched.
Yuna stared at Dawn inside her enclosure.
Dawn: (growls and stares at her back with her own eye)
Princess Yuna: So that's Dawn.
Princess Sharon: Yuna! Come on!
Princess Yuna: Coming!
Dawn: (turned away)
Meanwhile, Copper was training a pack of Velociraptors.
The Velociraptors, named Charles, Douglas, Jigsaw and Blade were chasing the pig.
Pig: (oinks running for it's life and ran into it's pen)
Copper: Yee-Haw! (give each raptor fresh ham piece) Good boy, Charles. Good boy, Douglas. Good boy, Jigsaw. Good boy, Blade. Y'all conciser yourselves lucky to earn your privileges on mating season.
Copper gives fresh ham piece to Charles, Douglas, Jigsaw and Blade when he saw Golden Apple.
Golden Apple: Howdy, Daddy!
Copper: Howdy, Goldie! How're doing?
Golden Apple: I'm doing great! I'm having fun in Genesis World!
Blade: (spotted Golden Apple waving)
Princess Yuna: What're you doing here, Copper?
Copper: AJ and I wanted to surprised y'all when all of you were coming to Genesis World. Radcliffe made me the best dang animal trainer.
Golden Apple: (fell off the bridge and into the raptor pen) AAAAAAAAAAAAAAAAAAAAAAAAAHHHHHHHH!!!!!
Charles: (spotted Golden Apple and begins to charge)
Princess Yuna: Golden Apple! Hang on!
Copper: Yuna! Wait!
The two ponies ready to shoot the raptors with Tranquilizer Guns.
Princess Yuna: Wait! Don't fire! Don't fire!
Yuna taming the raptor pack while Copper gets Golden Apple out of the pen.
Princess Yuna: Whoa! Hold it! Stand down! Stand down! Charles, Down!
Charles: (stands down)
Princess Yuna: Hey! Hey! Douglas, I see you. Now, back off!
Douglas: (backs away)
Princess Yuna: Good.
Yuna became very trainable with the Raptors.
Radcliffe: My word!
Applejack: Golden Apple, I was so worried about you! Are you okay?
Golden Apple: Yeah, Mama. I'm alright. Sorry for scaring you and Daddy.
Copper: At least you're safe and sound thanks to Yuna.
Radcliffe: How'd you do this?
Princess Yuna: I don't know. I guess I just know how to be great at taming animals.
Radcliffe: Come with me, I have something special in mind for you.
Princess Yuna: Wow! Really?
Snowdrop: I wonder what Radcliffe had for Yuna.