Rinkus and Sierra are the main antagonists in The Land Before Time VII: The Stone of Cold Fire, the 7th installment in The Land Before Time franchise. Rinkus is a Rhamphorhynchus and Sierra is a Cearadactylus.
Rinkus is voiced by Rob Paulsen, who also voiced Strut from The Land Before Time II: The Great Valley Adventure and Broccoli Overlord from The High Fructose Adventures of Annoying Orange.
Sierra is voiced by Jim Cummings, who also voiced Steele from Balto, the Bears from Sing, Nessus from Hercules, Dennis from Tarzan, Ed from The Lion King and Pete from Disney’s Mickey Mouse cartoons.
Rinkus and Sierra are Pterano's henchmen, but they are much more wicked than Pterano, and are often referred to as devil-like.
Together they set out to find the Stone of Cold Fire so they could use its power to rule the world.
They took Ducky away with them, and chased after her as she tried to escape due to a distraction by Rinkus standing on the edge of a cliff and falling.
She fell through the floor and was thought to be dead, but in violation of Pterano's orders, Sierra took her again when he found out she survived. She bit him, however, causing him to drop her. When Pterano tried to stop them from chasing after Littlefoot and his friends, they grabbed him and forced him to go with them, but they crashed into a rock wall.
Pterano reminded Rinkus and Sierra that he was the leader, but due to a thunderstorm they were forced to camp in a hollow cave-like area on the mountain side. Sierra expressed a desire to feed the kids to sharpteeth, to which Pterano decided to ditch them. Sierra wanted to kill him for this, but Rinkus convinced him to instead let him lead them to the stone. They tricked Pterano into thinking that they were on his side until he tried to take the stone's power and found it to be an ordinary rock. Rinkus and Sierra threw Pterano to the ground and hit the stone with rocks, demanding to see its power. At that moment, the volcano that the stone was on began to erupt. Everyone escaped except Rinkus and Sierra, who were still attacking the stone, until the stone exploded, sending them flying through the air where they landed in the same area they had previously camped in, severely burned. It is believed by many that this killed them, but at one point the film makers considered putting Sierra in a sequel, so their final fate is currently up for debate.
Sierra is the aggressive one and is viewed as a sadistic psychopath, while Rinkus initially appears as the humorous one, but is actually just as cunning as Sierra, as shown by his plan for Pterano to lead them to the stone so they can take its power themselves.
Interestingly enough, Internet Movie Database incorrectly listed Sierra as appearing in yet another animated sequel Journey to Big Water.
Rinkus' tail is flexible, when in real life, Rhamphorhynchus had a stiff tail for steering.
Rinkus and Sierra are among the few main Land Before Time villains to be considered real villains, since most of the previous main antagonists were predators by nature, who kill for mere survival.
Rinkus and Sierra are also the only main Land Before Time villains who are pterosaurs.
Despite being Pterano's henchmen, Rinkus and Sierra are more evil than Pterano due to the fact that Pterano is technically an anti-hero as he slowly redeems himself throughout the film and does good things, while Rinkus and Sierra are not anti-heroes and they do not redeem themselves or have good intentions at all.