Complex sentence: Unable to stand the slightest glimmer at its creation, the creature gains strength and solidity with each kill, allowing it a greater resistance to the light; and with it the ability to affect and control those around it, including a pack of vicious dogs.
Split into simpler sentences: Unable to stand the slightest glimmer at its creation, the creature gains strength and solidity with each kill, allowing it a greater resistance to the light. And with it the ability to affect and control those around it; including a pack of vicious dogs.