Complex sentence: The Power of the Dragon Circle manifested in the form of an enormous sword, which drained the Dragon's power, diminishing him in size and enabling Iowerth to later crush him in between his fingers, removing the Dragon of the Moon from the mortal plane.
Split into simpler sentences: The Power of the Dragon Circle manifested in the form of an enormous sword, which drained the Dragon's power, diminishing him in size. Enabling Iowerth to later crush him in between his fingers, removing the Dragon of the Moon from the mortal plane.