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The Drone's main attack method underwater was the AGM-129 Stealth Cruise Missile, whose power had been reduced to 80% of its original strength. However, due to the mysterious explosive used, the power of the AGM-129 Stealth Cruise Missile had been greatly increased. So, even with just 80% of its power, two AGM-129 Stealth Cruise Missiles were enough to kill a Los Angeles-class Attack Submarine.
After the Drone Upgrade, it only took two strikes for the Drone to effortlessly take out a US Military Navy Arleigh Burke-class Destroyer and a Perry-class Frigate on the sea surface; it then killed a Los Angeles-class Attack Submarine underwater. This demonstrated the terrifying strength of the Drone after the Upgrade.