- Irithyll of the Boreal Valley
- Irithyll Dungeon
- Painted World of Ariandel
- In the riverbed in the Corvian Settlement. After entering the settlement proper and taking the left-side path after the bridge, drop down into the riverbed behind the gate, where a Sewer Centipede guards it.
- The Ringed City
Infuses weapons with Magic damage, granting Intelligence scaling but reducing Strength and Dexterity scaling, as well as reducing base damage. Compared to Crystal infusion, the scaling is lower in all areas, meaning that the weapon will do less damage overall.
The benefit of the Simple infusion is that when wielded, the weapon slowly regenerates FP at a rate of about 1 FP per 5 seconds, or 0.2 FP per second. Reinforcing it will reduce the tick interval by roughly 0.217 seconds per upgrade level. At +10 reinforcement, a Simple weapon will replenish 1 FP per 2.85 seconds, or roughly 0.35 FP per second.