A brave young Iguanodon, Aladar was raised by lemurs and lived with them on their island until a meteor strike destroyed it. Escaping to the mainland, Aladar and his adoptive family joined a herd of dinosaurs heading for their breeding grounds under the iron fist of their merciless leader Kron. Aladar, having been raised by the lemurs to always stand together, challenges Kron's ruthless policy of leaving any stragglers for the lurking Velociraptors, Carnotaurs and Heartless to pick off. After Sora, Donald and Goofy join the herd, they help Aladar in defending the herd against the many Heartless and predator attacks, and eventually fight Kron after the Heartless attune the darkness in his heart. Later, they save the herd from a Carnotaur which is being controlled by the Heartless.
Aladar is a powerful offensive character. His main attacks are Tail Swing and Arm Stab, the latter involving Aladar striking enemies with his thumb spike. He can also jump up to cause shockwaves as he lands. These may knock enemies into the air, allowing Sora to perform aerial combos. Aladar's limit, Prehysteria, is somewhat similar to Simba's. Sora and Aladar open with an explosion of energy that damages nearby enemies and then attack in a vast array of rapid spinning/slashing attacks. The finish, Extinction, is another explosion of energy emanating from the Keyblade.