Bi Su was right. Though combination techniques are significantly stronger than ordinary magic skills, they're not so easy to perform successfully, because they require at least two magicians to perform them together. Perfect harmony is needed between the two individuals. After all, each person has a unique way of releasing their magical power. Achieving flawless coordination requires lots of practice.
Ji Dong chuckled and asked, "Would you believe me if I told you, I taught myself? If you would like, I can teach what I know."