Blood Key

The Blood Key is an item that can be obtained in Dungeons. 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. The blood key is used to open the leading to the Watcher's room and is consumed on use.

Trivia
This item shares a texture with the Overflux Power Orb