|Brothers of the Head (2005) [Barry Howe]: Dies (off-screen) of unspecified causes (presumably either his heart condition, a head injury from having previously been hit with a guitar during a concert, or a combination thereof); his conjoined twin brother (Harry Treadaway) then dies attempting to separate himself. Neither their deaths nor their bodies are shown; we learn the circumstances of their deaths when their sister (Elizabeth Rider) recounts how she found the bodies.
Heartless (2009) [Lee Morgan]: Stabbed in the stomach (off-camera) by John MacMillan; he dies shortly afterwards, while pleading with Jim Sturgess to help him.
Clash of the Titans (2010) [Prokopion]: Crushed to death when the Kraken's stone hand falls off and lands on him. (Thanks to Binky)