Thunder was sentenced to service on the Freedom 13 after an unspecified incident involving 'heavy explosives, a misidentified bunker, and Fortress," according to Acid. This incident was severe enough to warrant him and Fortress service on the 'Freedom 13'. In Book 1, he landed on Earth and scanned an F-35 at Nellis Air Force Base. He radioed in to Acid and began his way to them. In Book 2, he and Fortress were on their way when they received a transmission from Acid, asking them to deal with Boomer. As he prepared to let loose his Sonic-Boomer, he came under attack from Talon, who he defeated by discharging his sonic blast into the air.
Thunder is armed with a Sonic-Boomer, a strange weapon which only aerial Transformers can use. It uses four small implants on the bottom of his body. This weapon is so powerful he cannot use it while his friends are nearby without risking severe damage to them. He is also armed with missiles and a machine gun in both modes. He has 2 swords in robot mode for melee combat. He is not especially well armored and suffers from damage more easily than most. He also prefers ranged to melee combat, and is not as skilled in the latter as the former.
Thunder is mostly black with red wings and tailfins. His eyes are yellow.
Behind the scenes
Thunder's color scheme is a direct reference to G1 Thrust, and his Sonic-Boomers are a reference to G1 Thundercracker.