An Implant Without a Source

Implant: Heart of the Immovable King exists in the game's item data as a permanent key item, but no shop, loot table, or reward currently hands it out — and the Pal Surgery Table never asks for it. The passive is wired to the disposable version instead, so treat this item as an unused leftover: you can't get it, and surgery doesn't need it.

How to Get Heart of the Immovable King Instead

Heart of the Immovable King (sanity drains 20% slower — the top of the family above Positive Thinker and Workaholic , both of which are plain gold surgeries) is applied with Disposable Implant: Heart of the Immovable King : the surgery itself is free, but the implant is consumed. Disposable implants come from the Ancient Relic Recycler — every recycled Ancient Relic of any grade rolls one implant from a 16-implant pool, so it lands at 6.25% per recycle. Its best home is a finished Insomnia worker that burns sanity around the clock. See the Ancient Relics guide for the reward tables and the implants guide for how surgery works.