The Sou-istle differs from other T1 attack subs in that it is the only one equipped with torpedo defence. However, its torpedo defence fires extremely slowly and consequently gives it only a very minor advantage in naval combat, especially against units that fire salvoes of multiple torpedoes at once. The Seraphim T1 attack sub is the best in sub to sub battle. Although the torpedo defense will probably fire only once in the battle, that gives it a free shot at the enemy sub, effectively winning the battle. However, if caught surfaced, it is the quickest sub to go down since its torpedo defense is useless against surface weapons, and its low health will make it die quicker than the other factions' subs.