Aladdin creates a massive form made of Rukh to deflect Judar’s attacks and uses "Har-Har Infigar" to free Sinbad from Judar's ice spears.
Rather than simply killing Cassim, Aladdin asks Alibaba for his help to save him by reaching through the corruption of the Black Rukh. Where to Watch (Dub) Magi: The Labyrinth of Magic (Dub) Episode 16
The black Magi, Judar, joins the fray to take control of Cassim, using his ice magic to restrain Sinbad and overpower the remaining defenders. Aladdin creates a massive form made of Rukh
Despite the danger, Alibaba hesitates to strike down his former friend, which leads to his sword being shattered by the combined forces of Judar and Cassim. Magi: The Labyrinth of Magic (Dub) Episode 16
You can find the dubbed version of this episode on major streaming platforms like Crunchyroll or Apple TV .