Regions of the Sift, tides and ichor
Mojang has named two regions, the Meadows (Singer's Meadow), where you land, and the desert Carapace, and is keeping the rest a secret. The game also has Lullaby Hills and the Echo Den inside the Carapace. Inside the Sift, tides change the rules and ichor pools burn you.

Singer's Meadowfirst stop
Red sculk, teal grass and blue trees. The first region you reach, home to the Singer and its echo golems, just outside the Deep Dark portal. Your first visit unlocks the Sift tides tutorial. Mojang calls it the Meadows.
Who lives here: Singer, Echo golem, Bloombud, Sifters.

A portal on red ground among teal plants and blue trees. Lullaby Hills
Home to sleeping echo golems, and the side quest Lonesome in Lullaby Hills.
Who lives here: Echo golem.
Steam achievement: Choir Conductor, unlocked by 1.1% of players.
The Carapace
Flat, dry desert of dark blue stone and sand, cut by ravines and ichor pools, with bouncy slimes to reach ledges. Giant fossils stick out of the ground; the biggest, the humbler husks, can be walked into.
Who lives here: Stalker, Scavenger, Monarch, Echo golem.
Steam achievement: Carapace Explorer, unlocked by 5.9% of players.

Tall sandy pillars over flat ground, red plants at their feet. Echo Den
A corner of the Carapace where echo golems live, with an illager camp nearby to clear.
Who lives here: Echo golem, Illagers.
Steam achievement: Guardian of the Golems, unlocked by 1.5% of players.
Sift tides
The Sift runs on a tide that changes while you are inside, and it affects you and those around you. There are three.
Flow Tide
Nothing changes.
Thrive Tide
Souls refill faster and artifacts come off cooldown sooner.
Endure Tide
Tougher mobs spawn and passive soul regeneration stops.
“Shifting tides within the Sift can affect your character and those around you”
Ichor
The thick, rainbow-coloured liquid that pools in the Sift. Step in it and you catch soul fire and lose souls, the resource your artifacts run on, on top of the health damage. Sift natives are immune, which is why fights near ichor feel lopsided.
“It will deplete your health, but it also depletes your Souls.”
The Dartback is fought in an arena flooded with it. And the blub loves to bathe in it.

Haven't found the way in yet? Start at how to enter the Sift. Ready to fight what lives here? See every Sift mob and the bosses.