Chirako (or Tyrako) and Aro (or Arrow) were The Styracosaurus/Allosaurus Kaiju Duo that served as the first team up against D-Squad in the 4rth Ep. of Dinosaur Great War Izenborg, been 4rth & 5th by order of appearance respectively. Like most of Ururu's Dinosaur Soldiers, both could burrow their way underground and their hides were immune to projectiles.

Chirako breath fired from the mouth, as well had Ram Attacks, though it retreated when the situation required it.

Aro could Spew a Toxic Black Smoke as well fire a Red Energy Projectile from the mouth, but was weak to the Freeze Beam.

Quick Note: from here onward, Episodes from 4 to 39 (which were the only ones I saved) don't contained Subtitles, so I have to guess some stuff by watching as I don't understand Japanese, plus informing myself through Ultraman wiki on the Monster attack moves.

Following the failure of the Animal Slave Army plan, Ururu send Chirako, a Styracosaurus in the middle of Tokyo, D-Squad deploys to fight the beast; though their battle was brief, as Chirako decides to dig an escape only to reappear & continue its assault, causing a Tower with people inside to lean (not collapse), then retreats again; Ippei uses the IzenTwo to rescue the people, but Chirako reappears and blasts I-2, knocking Ippei out – the others try to help but Chirako tails whip IzenOne, then it escapes.

Ururu then sends Aro the Allosaurus to attack; the beast release a plum of Toxic Black Smoke, Torii warns the D-Squad of this and IzenOne head to fight Aro, with Zen suffering from head injury (BTW, don't expect anything from Zen's headache, as this goes nowhere), while Barra runs two IzenTwo, wakes Ippei up to join the fight. IzenOne's Missile and lasers prove ineffective against Aro, so the sibling Synchronize to take the fight in full against the beast – during this time they succeed in severing its right arm off and then freeze it, but before they could take Aro out, Chirako reappears, knocks the Izenborg from the fight, then frees the frozen Aro.

Now dealing with two Dinosaur Kaiju bombarding the IzenOne, is up to IzenTwo to help, but their action is laughable to the Dino Kaiju; Aro then blasts IzenTwo with its Energy Beam losing control and Ippei, still reeling from his last battle, takes full control and ejects Barra and chooses to deal with the Monsters in a solo suicide attack. The Izenborg, in full power, lifts off and stops Ippei's attack landing safely then turns its objective to the two DinoKaiju, flying at full speed with the IzenDrill, ripping through Aro's and Chirako's guts, and they explode. After talking to Ippei, they return to base.