This is actually one of those special endgame fights that needs some work to unlock (because the developers wanted it to be a true challenge for dedicated players).

First thing you should know is that youll need to finish the main story and this happens because Erlang Shen is tied to some deeper lore that only makes sense after the ending. The real interesting part starts when you complete all the secret areas except chapters 3 and 6, and dont forget about that Treasure Hunter's Quest in Chapter 3 which actually teaches you some mechanics youll need later.

Once youve done all that head to the Great Pagoda area from the Snow-Veiled Trail Keeper's Shrine and look for a bridge (this area is particularly tricky to navigate at first because of the fog). After crossing, turn left and youll find a wall you can interact with which leads to the Great Pagoda Keeper's Shrine, and after a pretty cool cutscene youre headed to Mount Mei for the big fight.

The Plantain Fan is absolutely essential here, because it stops his regenerative shield and keeps him from moving around too much (which is why many players struggle without it). Maybe interesting - the Wandering Wight's spirit can actually combo really well with immobilization skills, and using the Golden Armor Set helps with Qi recovery which youll definitely need. The fight itself is all about timing your dodges right and breaking his stance bar, especially when he starts throwing those thunder attacks your way. Just remember that exploring thoroughly before attempting this fight isn't just helpful, its actually necessary because youll need specific items to even stand a chance against his later phases.