What Li Pan executed was a knife technique he stumbled upon in the Penglai Daoist Collection, after undergoing his most recent tribulation and syncing memories with Li Qingyun.
Well, it is after all the treasure trove of the Profound Sect. What high-level techniques wouldn't it have? Knife techniques, in particular, are considered fairly common, straightforward to learn, and packed with power. The Penglai disciples all love learning a few of those moves to show off as mountain bandits or pirates, useful for emergencies. As a result, the variety is endless, and everything can be found in there.
Of course, Li Qingyun wasn't studying knife manuals to become some mountain bandit or pirate. He was training his palms. Yes, he was training to break knives with his bare hands.
