Fragment of the Void

This small, obsidian shard, glimmering with a hint of cosmic energy, resonates with the presence of a Void Sentinel. When held, it grants the user the ability to cast the guidance cantrip. However, each time the cantrip is used, the user must make a DC 13 Constitution saving throw. On a failure, the shard extracts some of the user's own vitality, causing 1d4 necrotic damage. This necrotic energy is a reflection of the Void Sentinel’s essence, imbued with the power to preserve knowledge but at a cost to the wielder.