Garth resembles a Caucasian teenager, with black hair, purple eyes and a slender build. His hair is relatively long, but a portion of it is caught up in a ponytail at the point of his back of the head, and the rest comes down to the nape of his neck and jawline. He wears a skin-tight swimsuit that exposes his arms and legs. It is predominantly blue-gray, although on the torso it has a midnight blue vest-shaped design, with azure lines tracing its edges and collar area. Around his waist, he dons a matching belt with attached tassets hanging down over his upper thighs. He also wears midnight blue bands around his forelimbs.
Garth was a native to the Atlantean city Crastinus. He and Kaldur'ahm studied sorcery together in the same class at the Conservatory of Sorcery. One day, Poseidonis was attacked by Ocean-Master, who defeated Aquaman. With their king down, Garth and Kaldur attacked the villain, but were easily defeated. However, their actions gave Aquaman enough time to recover and finally defeat Ocean-Master.
Impressed with their bravery, Aquaman offered both young students the opportunity to become his protégé. Kaldur accepted and became Aqualad; Garth continued his studies at the Conservatory. After Kaldur left to join the Team, Garth and Tula began a relationship.
When Aqualad returned two months later, Garth tried to convince Tula to tell their old friend about their relationship. She eventually did so, shortly before Atlantis was attacked by Black Manta's forces. Garth helped Aqualad, Tula, and Mera fend off the attack, but Tula was injured after taking a shot meant for Garth.
Garth and Aqualad deduced that the real target was the Science Center. Infiltrating the facility, the two disguised themselves as Black Manta's henchmen, but Aqualad's water-bearers gave him away. After a heated battle with Black Manta and his crew, they prevented the theft of a strange sea star that was stored at the center. Black Manta escaped after destroying most of the echinoderm in an explosion.
When Aqualad returned to the surface world, he seemed to have come to terms with Tula and Garth's relationship, and wished them both well.
At the Conservatory, Tula and Garth greeted their old friend Kaldur'ahm, who introduced Miss Martian and Superboy to them.
Poseidonis September 6, 19:27UTC-2
Garth and Tula recounted what happened to Topo: he had been attacked by purists, a group of Atlanteans who wished to rid Poseidonis of all "fish-heads" (non-human Atlanteans). During their conversation, they witnessed an altercation between their classmates from the Conservatory, and Ronal and his friends. After Kaldur, Garth and Tula threatened to use their magic, each group went their own way.
The abduction of Queen Mera had left the kingdom in an uproar. Prince Orm led the search, sending Kaldur, Superboy and Miss Martian after a tip that the purists were held up in the trench. Garth, Tula and the other students followed them, and could provide assistance when the tip turned out to be an ambush. Ocean-Master's magics weakened Aqualad and the other "impure" Atlanteans, but Garth and Tula were unaffected. Tula proposed going after Ocean-Master with Garth, but Lori Lemaris objected, as this would only feed the purists' misconceptions about the "impure".
The group eventually tracked Ocean-Master to a nearby cave. They attacked, but Ocean-Master could beat them off with the magic he had absorbed in his trident. Garth summoned the power of the Tempest, which overpowered Ocean-Master. With his magics gone, the villain was forced to retreat.
Tempest joined the rest of the Team during their mission, wondering how much he had missed. He was quickly brought up to speed on the recovered Babylonian artifacts, and offered his suggestions to their nature. Aqualad and Aquagirl had the same idea, and the latter traveled to the Metropolitan Museum of Art. He missed her, and hoped to see her soon.
Garth helped the others decipher the artifacts and was shocked to see Klarion steal them from Aquagirl, pretending to be him. Tula leaped after him through the portal. A distressed Tempest and Aqualad wanted to go find her more than the artifacts, but Nightwing reined them both in. Zatanna used her magic to locate Klarion in Bialya.
Tula was held in Marduk's Temple, near a pool where Tiamat was captured. Aqualad had gone in with Alpha Squad, and Nightwing joined with Beta. They worked their way through the warren of. Beta fought and defeated Tiamat, though Aquagirl had to sacrifice herself to bind the monster. Garth and Kaldur dug her body out from underneath the rubble, and Garth cradled her in his arms.
Mount Justice February 18, 09:59EST
Batman debriefed the Team, but Garth was too wrapped in grief to pay attention.
When magnetic field disruptors planted by the Reach threatened the Earth, Tempest joined 39 other heroes of Earth in a briefing in Metropolis. The heroes would use a computer virus provided by Lex Luthor to safely disable the disruptors. The heroes were paired off with another into twenty squads: one member would run interference against weapons guarding the disruptors, allowing the other to get close enough to plant the virus.Tempest was assigned to Eta Squad, and worked alongside Aquaman.
Within thirty minutes, all squads had succeeded in their mission.
During a meta-human summit in the General Assembly, Garth expressed his anger at the increased limitations placed on the Justice League, requiring them to have UN approval even for humanitarian missions. He could only find support in Themysciran ambassador Troia, which was noted by other ambassadors.
Although in Young Justice, Kaldur'ahm is portrayed as the first and only Aqualad, in the comics Garth was the first person to carry that title. He would serve as Aquaman's sidekick for many years, until taking on the name of "Tempest". Garth was killed during the events of "Blackest Night". He was replaced by Kaldur'ahm's comic counterpart, Jackson Hyde, in "Brightest Day".
This is Garth's fourth animated appearance. He first appeared in the Filmation series, Aquaman and The Superman/Aquaman Hour of Adventure (as well as Teen Titans shorts tied into the latter series) and later in the Teen Titans animated series and Batman: The Brave and the Bold.