Wow, Diablo 2 is such a classic game! There are all sorts of hidden quests, but I've done some research and want to share some with you. The first was the "Summoning of the Abyss." This quest required one to find a hidden Hell Gate in the Worldstone and then head to the Abyss to complete the quest. The way to play was to pay attention to controlling skills and equipment because this quest was very difficult and required patience and skill. The second quest was the "Bottle of Greed." This quest required one to buy a Devil's Bottle from the "Secret Merchant" for 500000 gold coins and bring it to Cohen's giant bear paw. However, one had to pay attention to the strategy. This mission would summon a bunch of monsters. One had to deal with them, find a corner to hide, and finally run out to defeat these monsters. There was also the "Tomb of Arteztis." This quest required one to find the hidden portal in the library. After entering, one had to overcome five obstacles and defeat the BOSS. The way to play required one to pay attention to the proficiency of skills and equipment, as well as reasonable tactical arrangements. I hope this information will be helpful to you. If you need more recommendations, feel free to consult me.