While chaos started to unfold in the outside world due to June's decision, Karsha remained inside the cave synthesizing the skill books the five shadow guards gave him.
After completing the Breakthrough quest with an SSE rating, he was awarded two talent abilities -Persona and Synthesis. What the synthesis does is, it takes ordinary items like skill books, weapons, and artifacts and merges them together forming a more powerful version of the item.
Common Grade weapons can be synthesized to form a rare or epic-grade weapon same as skill books can be merged to form a new and powerful version of the skill. The sky is the limit. All Karsha needed was to get his hands on skill books. Once he has enough, he will be able to merge them to form more powerful higher-tier skills.
