Blood Key

The Blood Key is an item that can be obtained in Dungeons, it is used to open the leading to the Watcher's room and is consumed on use. There is one Blood key per dungeon, usually dropped by a miniboss such as a Lost Adventurer or an Angry Archaeologist. When picked up, the red icon in the Dungeon scoreboard will have a ✓ appear next to it, indicating that your team has a blood key.

Trivia
This item shares a texture with the Overflux Power Orb