Decay Mage: Add Points Starting from Killing Slimes

[Pure hand-made without AI + city + copy + monster fighting upgrade + 1 monster 1 attribute point + slow narrative + multiple foreshadowing + seven civilization divisions + three era spans + doubts gradually revealed] The male protagonist is an adopted orphan. When he was adopted, he had a jade pendant on his chest with the character "Xuan" engraved on it. And because he likes to be alone, he was named Shen Qingxuan. He has no friends in the class and no playmates outside the school. All he has is his "relatives" Shen Hongsheng, the director of the orphanage. On the day of awakening, the male protagonist awakens to the only D-level hidden profession in history, the Decay Mage. Corrosion spell, causing 10% of attack power damage every second, very scraping! The power of decay, the skill hits the target and reduces the target's defense by 10%, which is an incredible mechanism! "Looks like a loser!" "Kill the enemy, affected by unknown power, attribute points +1" No! Not a loser! After a frustrating period of killing monsters, the male protagonist officially embarked on the path of becoming a strong man!