In the fictional universe of Gundam Seed, the Archangel class mobile assault ship was developed to support the mobile suits developed under the G Project. Based in part on the Orb Union's Izumo class battleship design, it was a very heavily armed battleship (more powerfully armed than either the Nelson-class Warship or Agamemnon-class carrier) with two large-bore "Gottfried Mk. 71" beam cannons in forward turrets, two "Valiant Mk. 8" 110cm linear cannons in aft mounts, 16 75mm "Igelstellung" CIWS mounts (mounting the same gun used in the Gundams' head mounts), 24 multi-purpose missile launchers (missiles include Sledgehammer anti-ship missiles and Korinthos and Wombat heavy anti-aircraft missiles) and a 16-cell Helldart anti-aircraft missile launcher. Archangel's most powerful weapon was her two "Lohengrin" (named after Richard Wagner's opera Lohengrin) bow-mounted positron beam cannons. The heavy defensive armament of the Archangel class combined with the ship's laminated armor made it almost impregnable to all but the most determined assault.

The true power of Archangel was hidden in the ship's cavernous hangar bay: Room for up to eight mobile suits or mobile armors. Combined with the G-series prototypes, Archangel was intended to be very nearly invincible. In operations, she was intended to hold the Duel and Buster Gundams, Lieutenant Mu La Flaga's TS-MA2mod.00 Moebius Zero mobile armor, and two TS-MA2 Moebius mobile armors back for defense while the Strike, Aegis, and Blitz Gundams took the battle to the enemy. With ZAFT stealing four of the five prototypes and destroying the two Moebius mobile armors, on 25 January CE 71, Archangel was left with only the Strike Gundam mobile suit and Lieutenant La Flaga's Moebius Zero to defend herself. After the battleship linked up with Admiral Halburton's 8th Fleet, she took on-board two FX-550 Skygrasper fighters, which were compatible with the Strike Gundam's Striker Packs.

Two Archangel-class ships were built during the war: Archangel, commanded by Lieutenant (later Lt. Commander) Murrue Ramius and Dominion, commanded by Lt. Commander Natarle Badgiruel (formerly Archangel's XO). Dominion was destroyed and Archangel severely damaged on the war's last day, 2 November, at the Battle of PLANT.

At the end of the war, Archangel's mobile weapon complement was the ZGMF-X10A Freedom Gundam piloted by Kira Yamato, the Strike Gundam piloted by Mu La Flaga and the Buster Gundam piloted by Dearka Elsman. Dominion carried the GAT-X131 Calamity Gundam piloted by Orga Sabnak, the GAT-X252 Forbidden Gundam piloted by Shani Andras, the GAT-X370 Raider Gundam piloted by Clotho Buer, and a squadron of GAT-01 Strike Daggers.

After the war, Archangel was repaired, upgraded with submarine capability, and hidden in a secret hanger at Orb. After an failed attack by ZAFT commandos in CE 73, Archangel left this facility. Its mobile suit complement at this point was the Freedom Gundam piloted by Kira Yamato, the MBF-02 Strike Rouge piloted by Cagalli Yula Athha, and a new MVF-M11C Murasame transformable mobile suit piloted by Andrew Waltfeld. Later that year, Archangel intervened in a battle between the ZAFT battleship Minerva and a joint Earth Alliance/Orb Union task force near the Dardanelles.

The Archangel and Dominion are named after angelic ranks in Christian cosmology. If other Archangel-class vessels had been produced, they most likely would have been named after the other angelic ranks, such as the seraphim, cherubim, et al.アークエンジェル級