Complex sentence: The bloody hand-to-hand shipboard combat that ensued left him with mental scars that would last for the rest of his life and convinced him that, although they are machines, the Cylons truly hate the human race.
Split into simpler sentences: The bloody hand-to-hand shipboard combat that ensued left him with mental scars that would last for the rest of his life. He remains convinced that, although they are machines, the Cylons truly hate the human race.