Magi - Season 1 Episode 20 The Two Princes

Upon learning Hakuryuu's reasons, Sinbad insists that he should learn more about his country first and asks him to introduce himself to Alibaba and the others. When Alibaba meets Hakuryuu, he hears a voice from himself urging him to hate and attack him, but he collapses instead. Upon being examinated, it is revealed that the snake bite Alibaba suffered in Balbadd has spread into a dark wound onto his body, from which the agent of Al Thamen, who was supposedly destroyed there, emerges. Sharrkan attacks the enemy whose dark blood splashes on Sinbad, cursing him too. Before disappearing, the agent explains that upon cursed, it is only a matter of time before both Alibaba and Sinbad fall into depravity and become overtaken by the Black Rukh. However, there is a dungeon called "Zagan" in an island to the south which is yet to be conquered, and whose Djinn can heal any kind of disease. As Sinbad and his household are forbidden from entering any further dungeon as he already has seven Djinn under his command, he sends Aladdin, Morgiana and Alibaba to conquer Zagan instead. Hakuryuu also offers himself to accompany them on their quest and together they depart there, escorted by one of Sinbad's Generals, Pisti. Upon arriving at the island, the four are approached by a child who asks them to rescue her parents, who are trapped inside Zagan. Hakuryuu and the others agree to help her and set to the dungeon, from which a strange light emanates and pulls them inside.