ShadOre

First release.

• Umbracite: small, medium and large buds and clusters built from voxel cubes, translucent and slowly pulsing. They glow to the eye but give off no light, so mobs still spawn around them.
• Generates rarely in the deepslate layer (Y 0 and below), in small nests, about twice as often in the Deep Dark, never in spots that are lit.
• The light rule: above light level 7 (torches, lava, daylight, burning mobs, blazes, glow squids, a player holding a light) a crystal crackles, then bursts into black smoke that blinds everyone within 4 blocks for 3 seconds. The burst is a vibration sculk can hear. Removing the light in time saves it.
• A low hum and faint motes help to find crystals in the dark.
• The tempering chain: four Umbracite Shards around an amethyst shard make an Umbracite Crystal; six crystals, two ink sacs and an ender pearl make an Umbral Heart.
• The Umbral Altar, where Shadow Tempering happens: an Umbral Heart in the centre, six shards on the hexagram and an iron, golden, diamond or netherite piece in the offering socket. In darkness a five-second ritual runs by itself, with its own animated screen (shards igniting, beams, a charging heart, a burst); on the block a heart floats up between light columns and glowing glyphs stream into it. Light above level 7 stops it. Tempered gear keeps its enchantments and has three times the durability.
• Shadow armor: all four tempered sets share one symmetric design of semi-transparent violet crystal glass, edged with the metal they were made from, with glowing eye slits and a heart-shaped chest gem that shine in the dark. Tempered tools and weapons match it: violet crystal glass heads edged with their metal, a glowing rune and a gem where the head meets the dark umbral handle.
• Four sets with their own perks: Shadow-Plated Iron (quiet, faster digging and stealth in darkness, silent steps), Gloom-Gilded (against fire and glowing creatures, mends itself in darkness, piglins stay calm), Void Diamond (drops and experience straight to the inventory, glowing enemies in darkness), Abyssal Netherite (stronger in darkness, immune to Blindness and Darkness, the Warden leaves you be). Spears on Minecraft 26.x.
• The Umbral Anvil: load up to eight shards, each restores a quarter of a tempered item's durability, only in darkness.
• Budding Umbracite (shards, cobbled deepslate, an echo shard) grows new crystals below Y 0 in total darkness.
• Sixteen advancements, a creative tab, tooltips, recipe book unlocks, English and Russian, in-game server config.
• One jar for Minecraft 1.21.1, 26.1.2, 26.2 and 26.3 (NeoForge; 26.3 on the current NeoForge beta).