I'm looking to pick some brains to improve this first dungeon I plan running with a new group. The idea is that lvl 4 PCs have been invited by a royal family to attend a birthday celebration. However, the pcs have forgotten gifts. But an npc at a brunch they attend earlier in the day, mentions that the land is rich in history and treasure. Pointing them to a destination they can acquire a gift and other loot. The plan is too have them reach the end of the dungeon, and have players "accidently" remove a magic sword. Freeing a sealed evil. My first idea was too have kobolds who have worshipped the sword and location as a holy ground, but that made me think why would the local forces not take them out if they were basically occupying an important historical relic and location. Also, I felt kobolds might be too weak for them but idk. I'm looking for something that could make this first dungeon alittle more mysterious and challenging for the party.