Fantasy: After Doing All the Bad Things, I Still Become the Savior?

Lu Yang travels to another world and gets a 'rewarding good and punishing evil system', where he can get rewards for doing good deeds. However, Lu Yang knew very well that good people don't live long, and disasters last for thousands of years. So... Late one night, Lu Yang knocked down his mentor with a cup of poisonous tea. He also deceived his junior sister, who was already engaged, to comprehend the Yin and Yang Dao together. After successfully practicing, he even destroyed a city with his backhand, destroying countless lives. However... "Ding, your master is an undercover agent of the Demon Sect, and he even plans to seize you. You poisoned him to save the sect from a catastrophe. The reward: Nine Dragons Thunder Gang Fire." "Ding, your junior sister has long wanted to break off the engagement. It was you who gave her the courage to say no to the arranged marriage and prevented the tragedy from happening. The reward: supreme swordsmanship and the return of ten thousand swords to the clan!" "Ding, the city you destroyed is a stronghold of the demon from outside the territory. Kill the demons and protect the common people. The reward is: the chance to become an emperor!" … .. This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.