Fantasy: I Kill Monsters in Exchange for Rewards, and I Will Be Invincible in a Hundred Years

[System] [Both good and evil] [The protagonist will not always stay in the Demon Suppression Division] Wang Yuan traveled to the demon world, became a jailer in the Demon-Suppressing Tianlao, and activated the trading system. As long as the demon is killed, the demon's body can be used for trade, and he also discovered that using silver can improve his cultivation. However, I thought that with this ability, I could become famous in the Demon Suppression Department, but I didn't expect that killing colleagues with strong backgrounds would lead to everyone chasing him. Helpless, Wang Yuan escaped from the Demon Suppression Division and started wandering around. From then on, a Yin-Yang Demon Emperor was born. What? Your sect has a lot of rare treasures, take them, they are mine! What? At first you bullied me into being weak, but now that I am strong and suppressing your dynasty, do you think I am going too far?