In the first episode, it seems like the character experienced a sudden surge in power that reminded him of his past life. This newfound strength was likely fueled by a desire for revenge against those who had previously humiliated him.
In the second episode, the character takes advantage of his powers to test them out on one of his students who resembles one of his favorite streamers. It's possible that he wants to see how effective his abilities are and whether they can help him achieve his goals.