Complex sentence: Fujimiya realizes that everything he believes in is based on this flaw, and became dejected... he gives the injured Gamu the light that is the essence of Agul so that he can use it to defeat Zoalim.
Split into simpler sentences: Fujimiya realizes that everything he believes in is based on this flaw, and became dejected. He gives the injured Gamu the light that is the essence of Agul so that he can use it to defeat Zoalim.