The party meets for the first time at a dusty inn in the hamlet of Roanoke, in the backwoods of Breland. There is a commotion stirring the villagers; an apocalyptic monk raving about the end of the world as we know it and the dawning of a dark age where men are subservient to demons.
Spooked, the villagers have the tavern owner try to talk to monk into moving on to somewhere else. The ensuing argument leads to conflict, and suddenly the party is dragged into confrontation.
The monk opens a portal in the ground in front of him that allows several misshapen demons to enter this plane of existence. After a quick battle, the monk is struck down and his only possession stripped from his corpse.
This is the pommel of the dagger used to open the demonic portal, which was later taken off of the corpse of the apocalyptic monk. After the portal is closed, the gem changes to a crimson red hue.