In Alchemy of Souls Ep 8, Gilpu was trying to shift souls with Jang Wook (Lee Jae Wook) but couldn’t succeed because Kang Wook saw Mudeok (Jung So Min) while Gilpu was performing the spells which made him bounce back to his body and turned him wild. Afterwards, he had a one-on-one confrontation with Jang Wook and he also injured Mudeok on her shoulder. Mudeok asked Jang Wook to follow him and he did so.
In the meantime, Songrim members came to the spot where Gilpu performed Alchemy of Souls with a dog who can smell soul shifters, so Mudeok tried to escape and was running towards the forest where she was caught by Seo-Yul (Minhyun). Seo-Yul told his companions that she was Jang-wook’s maid, not a soul shifter so he should treat her as if he unknowingly injured her. He took Mudeok and healed her wound with his energy and burned his hand as a result.
Jang Wook was still following Gilpu in the hope that he would go Daksu, the one who holds ice stone which could only save soul shifters from turning wild. Jang followed him to the royal palace where Gilpu was caught but he escaped. Then Jang Wook fought with him with his spells of Tansu covering his face so that no one could know his real identity and he killed Gilpu.
The next day, it was rumoured that Naksu returned and was the one who killed Gilpu. Daeho’s people started to make their own assumptions regarding this that Naksu shifted her soul into a strong male body. On the other hand, Seoyul lied to Songrim about Mudeok and Jang Wook telling them they didn’t know who the soul shifter was.
As the days went by, it was time for Crown Prince and Jang Wook’s one-on-one fighting challenge. All the mages and royals attended the duel. Songrim leader announced that if Jang-wook would not show up till noon he would consider this his defeat and as a punishment Jang Wook would lose his right to be the next Gwanju.
It was noon and Jang Wook didn’t show up so Songrim’s leader asked Seoyul and Dangoo to close the doors. As soon as they reached to close the doors, Jang Wook and Mudeok showed up there. Jang Wook signed the duel contract and the duel started. Jang Wook remembered Mu-deok’s words and fought accordingly. Mudeok also asked Master Lee to arrange water for him to perform Tansu but Jinsu got rid of the water pots.
After finding no water there Mudeok took her knife and cut her hand. She yelled Master and dropped her blood which Jung Wook used to perform Tansu and as a result, he won the duel astonished everyone there. Ginsu doubted Jang-wook and asked him where he learnt Tansu, Jang-wook told him that he learned himself but Ginsu didn’t listen to him and argue at that point Master Lee told everyone there that he saw Jung Wook practising the spells and whatever he was saying is true.
At the end of Alchemy of Souls Ep 8, after witnessing Jang-wook’s powers and skills of Tansu all the leaders of the mages asked Jang Wook to join them. Ginsu also asked Jang-wook to join him after getting a signal from the queen who was the real Danju. Jang Wook asked Mudeok that who should he join and she replied, he should join Songrim as of now.