There's Something Wrong with This Family. Why Are They All Martial Saints?

[Family development flow + slow heat + non-cool writing + upgrade + system flow] Traveling through troubled times, demons are rampant, imperial power has collapsed, and human lives are like grass. Gu Yan became an ordinary young man in a remote village during the Great Wu Dynasty, with ordinary qualifications and a bleak future. Fortunately, although Gujiazhuang is small, the family is harmonious and they stick together to survive, which has become the only warmth in this cannibalistic world. Until the evil spirits invaded the country, the village was running out of food, and the shadow of death shrouded everything... In a desperate situation, Gu Yan quietly drew his sword and looked at the raging demonic tide in the darkness. It turns out that by killing monsters, you can gain experience and infinitely improve your skills! From now on, [Basic Sword Technique] can kill evil spirits, and [Demon Subduing Fist] can break mountains! While everyone in the world is trembling under the claws of demons, the demon hunters of Gujiazhuang have quietly embarked on their journey. Many years later, the supreme family, which was so powerful in the world, looked down at the world and looked back at its original intention. It all started with the young man's first sword in that small village.