Martin

Yang's students are Yang's captives and spirits trapped in the haunted temple.

History
At an unknown point in time, the students were taken under Yang's teachings, with Yang becoming infamous for his strict methods on them. However, unbeknownst to the public, they were secretly trapped in his temple, and after their death, were converted alongside him into ghosts.

The Temple on Haunted Hill
As the morning came and the curse on Yang's Temple started to take effect on the Ninja, Yang's other students showed themselves, revealing them to be chained up, as they were imprisoned by Yang. The Ninja then quickly fled to the entrance, not wanting to suffer the same fate as Yang's students. They manage to reach the entrance, but Cole dropped the scroll mid-way and thus had to go back in to retrieve it, which caused him to turn into a ghost. Fortunately he escaped the temple before he can meet the same fate as them.

Wishmasters
After Yang's temple was torn out of Ninjago to help construct Djinjago, they left his temple while he angrily confronts Nadakhan, claiming domain. However, the latter, unimpressed, promptly ordered Dogshank to shoot water at Yang and them, forcing them to abandon the temple.

Season 5: Possession

 * 47. "The Temple on Haunted Hill"

Season 6: Skybound

 * 51. "Wishmasters"