Soul of Night

Soul of Night is a Hardmode crafting material dropped by most enemies killed in the Underground Corruption or Underground Crimson (in the Cavern layer), with a 1/5 (20%) / chance. This also includes enemies not native to the biome such as Granite Elementals.

Crafting all items, excluding the boss-summoning items and, requires 134 / 97  /   89 Souls of Night. One of each boss-summoning item and a Key of Night require an additional 24 / 14  Souls of Night.

History
Seele der Nacht Âme de nuit Эссенция ночи 暗影之魂 Stickyrunneryt (hopefully)