Captain Ace Arn aka Ultra the Multi-Alien is one of the supporting protagonists in Batman: The Brave and the Bold.
His grunts were provided by ???.
Captain Arn was a planetary tour guide until one day the ship was hit by a nearby comet's electromagnetic wave. He evacuated the passengers and crashed into an asteroid after being teleported to an unknown solar system. The asteroid was the secret headquarters of a criminal named Zobra. Arn learned this solar system was artificially created using one member from four races: the Laroo, Raaga, Trago, and Ulla. In the following skirmish, Zobra was killed by accident and Arn was hit by four duplication weapons at once. Instead of getting killed, he was transformed into a composite alien of the four races, each with a unique super power.
After returning home, he decided to become a hero and took the codename, Ultra the Multi-Alien. Ultra continued to yearn for his humanity and past life, including his girlfriend, Bonnie Blake. She concluded Arn had died in space. Eventually, Ultra constructed a Hyper-Converter Belt which allowed him to switch between Ultra and his original human form. In order to protect her, Arn reunited with Blake but told her a cover story that Ultra found him adrift in space. As Starro's forces overran Earth's solar system, Ultra joined several Green Lanterns, Captain Comet, and Space Ranger in a failed mission. They were overcome by Starro and infected with its parasitic clones.