Hard Knox Life/Plot

Aldar appeared at Knox Academy and revealed he was planning a ritual known as the Advent, the resurrection of the Old Ones. He had managed to manifest the souls of the Old Ones in the form of seeds, which could hatch in the bodies of powerful witches. He planned to use the students at the academy as vessels. In order to save his students, Knox made another soul agreement with Leo Wyatt, so that the Charmed Ones would be forced to help him.

Piper confronted Aldar, though he cloned himself and teleported to the academy. The sisters, Leo and Knox then fought the clones to protect the students until Phoebe identified the real Aldar with her empathy. Before Piper could freeze him, Aldar tried to infect the students with the seeds. In an attempt to save his students, Knox jumped in the way and was hit instead, leading to his death. Piper then blew up Aldar, vanquishing him.

Knox was buried on the academy grounds, though later that same night, he rose from his grave seemingly possessed by the Old Ones.