Complex sentence: He received Halloween, a pumpkin doll/supporter, from his teacher Edea, before she was killed by his sister and as such, he treasures it above all else, but he does occasionally shoot it or mistreat it in a comical fashion.
Split into simpler sentences: He received Halloween, a pumpkin doll supporter, from his teacher Edea, before she was killed by his sister. A such, he treasures her above all else, but he does occasionally shoot her or mistreat her in a comical fashion.