Artifact Reliquary

The Artifact Reliquary is a Special Boss Monster found only in Bulwark’s Ambry. It’s serves as the Boss for the various Artifact Trials, of which said Trial’s Artifact is contained inside it,

Skills & Behavior
The Reliquary is immune to all normal forms of damage. To defeat it, one must interact with it while carrying an Artifact Key. Doing so will consume all the key(s) on all players, and deals 1/4 damage to the boss. It takes about 3 interactions (excluding the initial one) to defeat it.

Once the Reliquary is given the first Artifact Key, alongside enabling other Monsters to spawn, it’ll become active itself and begin firing lasers in a set pattern around itself to attack, which home in on any nearby player. It's fire rate increases the lower it's HP becomes, alongside it's lasers becoming both faster and having stronger homing capabilities.

Trivia

 * The Artifact Reliquary is the only Special Boss Monster to be completely original (so far). All the others are just stronger variants of regular Boss Monsters.