My key to fighting through martial arts

Xiao Tian traveled across Dou Qi Continent and became a member of the Xiao family.
Without a system, he thought he could only rely on foresight to fight.
At this time, he suddenly discovered that after opening the door with his key, he came to the world of Wu Dong Qian Kun.
Let's see how he uses the opportunity of the two worlds to become a great master and give the beautiful woman a warm home.