Lü Dongbin
Another legend says that he borrowed the sword from Lü Dongbin to subdue a strong demon, and after being successful, he refused to bring it back after witnessing the sword's power. The sword itself would magically return to its owner if Xuanwu released it, so it is said that he always holds his sword tightly and is unable to release it. However, not only does he outrank Lü in terms of divinity, Xuanwu also dates back longer in history than Lü Dongbin, putting this claim in suspect.