Complex sentence: The real Konrad had committed suicide before the game had begun, while the Konrad that Walker has been in contact with during the game is actually a traumatic hallucination that none of his team saw or heard, appearing only in his mind.
Split into simpler sentences: The real Konrad had committed suicide before the game had begun. The Konrad that Walker has been in contact with during the game is actually a traumatic hallucination that none of his team saw or heard, appearing only in his mind.