Complex sentence: George had to protect Maria Louise when she witnessed Chapman murder Sir William, a Neo-England official and during the battle when George slashed open Chapman's shirt with a knife he confirmed that Chapman had been reanimated with DG Cells.
Split into simpler sentences: George had to protect Maria Louise when she witnessed Chapman murder Sir William, a Neo-England official. However when George slashed open Chapman's shirt with a knife he confirmed that Chapman had been reanimated with DG Cells.