Oscurium

Defeating the Dark Golem yields Dark Essence, which is used to upgrade Netherite equipment and to craft the Cursed gear set. The Cursed sword, pickaxe, axe, shovel, hoe and full armour set are built from Dark Rods and other special materials gathered along the progression, and the set is noted for very high durability and strong combat stats. Several new structures and dozens of decorative and functional blocks support exploration and building.

A dark dimension is reached through a portal behind the Ancient City, with a lighter aesthetic and its own mechanics. Enemies there include the Cloud Rider, a flying foe that can summon lightning storms; once defeated, the remains can be ridden as a controllable flying mount, and the Storm Crystal releases waves of lightning against enemies. Other drops grant a Mimetization Crystal for temporary invisibility, an Immortal Crystal with resistance and damage negation, and a Sculk Rock Crystal that summons falling blocks.

Oscurium is server-side only, so players join without installing anything. The mod is released under All rights reserved, which means it is not open source. Files exist for Forge only, the latest being 1.2.6 for 1.20.1 on the beta channel, published 2025-08-05.