In the End of the World, I Was Alive

Forty years ago, humans first observed a new creature [Deep Sea] on the high seas. At first, humans did not care about the harm these seemingly harmless and beautiful girls would cause, but after they continued to destroy ships passing by the high seas, they had to pay attention to them. After the first three years of miserable victories, some [ship girls] who were friendly to humans appeared, and people who bonded with ship girls were called [admirals]. I used to be an admiral.