Complex sentence: In Ba Sing Se, Jet is brainwashed by Long Feng, the Earth King's chancellor, after attacking Zuko and Iroh; but released from this condition by the protagonists, and later killed during a fight against Long Feng.
Split into simpler sentences: In Ba Sing Se, Jet is brainwashed by Long Feng, the Earth King's chancellor, after attacking Zuko and Iroh. He is released from this condition by the protagonists and is later killed during a fight against Long Feng.