"I despise the A-class submarine to the depths of my soul, especially number 12. Its presence turns our sailors into cowards after one of the damned boats sunk the old battleship Poseidon."
Navarchos Helen, Olympian Navy High Command

Pilotmario Navy Submarine A-12 was a member of the A-class, a successor to the Port-class submarine. Unlike her predecessors, she was designed for high-speed underwater attack as well as high underwater endurance. She was unique among all of the class, as she was the first Pilotmarian submarine fitted with radar; after her second patrol, she was in need of repair, and it was decided to retrofit her with sonar while she was repaired. Of all of her 22 sisters, she was the longest serving. As such, she served with distinction in the Second and Third Olympian War, claiming an impressive record of four capital ships, nine lesser warships, and 21 cargo ships. This included the Olympian battleship Poseidon, a warship held in great esteem with the Olympian Navy.

However, her claim to fame was her role in Operation Horse, a plan to infiltrate the city of Troy as a final attempt to end the Siege of Troy, where she served as the launch point for the disguised commandoes. Numerous times during her 30 year career, she was damaged heavily by enemy action or weather, but never officially lost, earning the ironic nickname "Unsinkable Sub". She was retired at the end of the Third Olympian War, serving the last three years as a training vessel due to her age.

Despite her legacy and a petition from veterans who served on her, she was ordered to be scrapped. True to her legacy, she broke free of her towline in a storm, beaching herself on the rocks by Charity Point. Due to the conditions of the area, salvage was deemed unfeasible, and since it was deemed she had no hazardous materials aboard, she was left there to rust, to slowly be consumed by the oceans. This is a static model of her.