First of all, the last one can't have the exact same meaning because it doesn't say anything about "main" spells nor anything about "used against people". ) The first two are basically the same. "there" is indeed optional, though it is slightly unusual in this sentence because the subject is definite ( the main spells ).
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First of all, the last one can't have the exact same meaning because it doesn't say anything about "main" spells nor anything about "used against people". (I'm surprised that you even considered that this sentence might not be different from the other two.)
The first two are basically the same. "there" is indeed optional, though it is slightly unusual in this sentence because the subje