Soul of Light

Soul of Light is a Hardmode crafting material dropped by all enemies in the Underground Hallow with a 1/5 (20%) chance. On an Expert Mode world, this rate is increased to ~2/5 (36%). This includes stray enemies not native to the biome, such as Goblins and other enemies.

Crafting all items on PC, including a full stack of five Light Discs, excluding the Boss-summoning items and Key of Light, requires 98 Soul of Light (89 on console/mobile). One of each Boss-summoning item and a Key of Light requires an additional 24 Soul of Light (14 for console/mobile), for a total of 122 (103 for console/mobile).

PC version
Console and Mobile version: