Shinobi used a very powerful staff which increased his powers. His staff is the completely opposite of Ninfea's staff: Her power is mostly generated from light, while his power is mostly generated from darkness. Ninfea and Shinobi might be very matched to each other.
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When Rex fell into the catacombs, he saw the the staff and the only thing remaining of his great-great-grandfather: the bones of his right arm. After he climbed out of the catacombs, he showed the power of the staff to the other Elves and destroyed the bones of the arm and made a plan to conquer Pixieville with the "legacy" of Shinobi.