Complex sentence: For use as weapons against the wizards of "the new world", they are serpent like creatures that wear a cloak that can make them or other wizards with both sides (additve and subtractive) of the gift.
Split into simpler sentences: For use as weapons against the wizards of "the new world". They are serpent like creatures, that wear a cloak that can make them or other wizards with both sides (additve and subtractive) of the gift.