Sift bosses

The Sift has two full bosses, the Monarch and the Sculk Monstrosity, and two mini-bosses, the Harmonizer and the Dartback. The Twisted Warden guards the Deep Dark portal on the Overworld side. On Steam, 5.8% of players have the achievement for beating a Monarch.

Three heroes on a red and dark stone ledge; the quest tracker reads Search the sculker nest — Heading into the Monarch's arena: the tracker reads “Search the sculker nest”.

Twisted Warden

Gatekeeper

In front of the Deep Dark portal, Ancient City (Overworld side)

Twisted Warden moves
Move	What happens
Fists	Wide swings from both fists.
Sonic boom	A straight blast, like the vanilla warden's.
Soul-flame eruption	Fields of soul fire burst up from the floor.

Worth knowing: Beating it is what lets the echo golems and the note blocks open the Deep Dark portal.

Harmonizer

Mini-boss

The Sift, in the mission Wading Rainy Plains; fought again later, soul corrupted

Harmonizer moves
Move	What happens
Roar	A ring-shaped shockwave that also calls in about seven mobs, mostly sentinels and nesters.
Beam	While those mobs live, it tethers a buff beam to each one.
Tentacle	Raises a tentacle and tries to grab the nearest hero.

Worth knowing: Each buff beam breaks when the mob it is tied to dies.

Dartback

Mini-boss

A walled-off arena full of ichor, during the Lost Harmonies objective to find the stolen soul blocks

Dartback moves
Move	What happens
Summon	Calls two stalkers and two scavengers into the fight.

Worth knowing: The arena floor is ichor, which burns you and drains your souls while you stand in it.

Monarch

Boss

The sculker nest, reached through the Carapace (late game)

Monarch moves
Move	What happens
Summon	Roars for two stalkers and two scavengers; it cannot do it again while they live.
Dash	A twirling slash along a line; five seconds later feathers rise from that line and fly at a hero.
Spin	Spins at a hero, then eight feathers form in the circle and fire after five seconds.
Multi-spin	Slash, dash, spin, slash, chained together.
Echo	Midway through the fight it splits off a spectral copy with the same moves.

Worth knowing: The echo dies when the real Monarch dies, as the developers explained on the after-show.

Four heroes fighting under a boss bar labelled Monarch on a patchwork pink and teal floor — Four players under the Monarch's health bar; the tracker reads "Defeat the Monarch".

“So defeating the Monarch will defeat them both.”
Mojang designer, The Deep Dig after-show

Sculk Monstrosity

Boss

The Sift

Sculk Monstrosity moves
Move	What happens
Double swing	Right arm then left, heavy damage.
Charge	A shoulder charge in soul flame, then a burning punch that sets you alight.
Summon	Releases souls that become sculk cubes rolling at you.
Catalysis	Sculk catalysts rise around the arena and spread veins across the floor.

Worth knowing: The charge ends in a two-second slowdown that leads straight into the burning punch.

Before you go in

The Monarch, the Harmonizer and the Dartback all call in help, and the summons are the same stalkers, scavengers, sentinels and nesters you meet in the open. Souls power your artifacts, so watch the tide: an Endure Tide stops passive soul regeneration and spawns tougher mobs, which is the worst time to start a boss.

Soul-corrupted mobs and bosses drop echo shards, the resource used to enchant gear, so the rematch against a soul corrupted Harmonizer or Dartback is worth taking.