Bleed

Bleed / Bleeding damage affects only targets with blood. Other targets, such as constructs or undead, are immune. Bleed effects in game vary. Some deal the damage immediately, some deal damage over time.

As for weapon enchantments, as of 2023, Bleeding is the newest variant of this enchantment. Unlike its predecessors, it's scaling with item level. Older enchantments are still found on many named and crafted items and legacy random loot.