Fatal Claw Rarest and Hidden Achievements

This page is the low-rate companion to the Fatal Claw Achievements Guide. Where the general guide lists all 51 achievements by category, this one focuses on the subset where most of the playerbase drops off — everything below 25% global completion — and explains what those rare unlocks are actually gating. It also calls out achievements that are easy to miss because they trigger outside the obvious kill / reach / upgrade pattern.

Percentages are from the live Steam global stats page (snapshot 2026-09-21) plus the Exophase mirror for the entries Steam hides behind login (notably The Last King's End and He Was an Excellent Assistant, which Steam currently shows only after sign-in). If an achievement you earned does not show up in the overlay, it may be one of the late-cycle or hidden entries that take several days to register in the global rollup.

Rarest 5 — the ones most players miss

The five lowest-rate achievements in the live rollup, in order from rarest to less-rare:

Three of the rarest five are Sanctuary seals. They share the same bottleneck: by the time Sanctuary runs unlock, the player either has the relevant Mutated Ability (Meditation of Jibanam) or has not picked it up yet. The Two-of-three-seal pattern in the route means missing one ability usually costs you 2-3 achievements at once.

Where the Black Current Ends is rare not because the route is hard — by the time you reach Aphotic Marsh the game is essentially handing you the region — but because most first runs end in Origin Laboratory, Elord Castle, Higasha Tundra, or a post-Story state. Late-game 1.0 content is gated by how far a run actually pushes, not by any individual ability check.

Curiosity Killed the Cat is the rarest non-Sanctuary entry because its trigger is hidden. Players who assume the Mirror Chamber is a wall-climb puzzle waste time hunting levers that no longer exist (a post-launch patch removed wall-climbing mirrors). The real trigger is effect-timer management, not platforming.

Mid-rate band — 15-30%

The next tier is also worth tracking because they are achievable in any normal route but require deliberate play:

The first four are region-reach achievements on regions that sit just before the Sanctuary block; most players cross them in a normal mid-game route, but a Cabitz-heavy exploration build can skip them by accident. The Last King's End is special: it lives behind the Sealed Spire boss, which only becomes reachable after all three Keys of Hope lift. It is the rarest boss-kill achievement in the game, in part because the boss is not on any first-time route map. Fulfill the Calling and Remix Begins! sit in the same late-game band but require fighting Sommar and solving Jack’s Vault respectively, both of which sit past the Sanctuary gate.

Boss milestones — these most players get

Boss achievements sit at the high end of the global percentages, mostly because the boss is on the main route:

These are the achievements you should expect to land on a normal route. If you are missing one of them, the blocker is almost always a Stone Warp soft-lock or a Cabitz socket you have not assigned; the Progression Route and Ability Gates page shows which ability gate each boss lives behind.

Region-reach achievements — every region has one

A region-reach achievement fires the first time you enter a region. They are the easiest category to backtrack against, because the trigger is “you stepped into this region”, not “you finished it”:

|| Achievement | Rate | Region | |---|—:|---| | Gale Warning | 55.3% | Strigine Quarry | | Into the Darkness | 39.8% | Black Canyon | | Golden Castle | 44.4% | Elord Castle | | Frozen Boundary | 27.6% | Higasha Tundra | | Prison of the Forbidden | 17.3% | Jayma’s Dungeon | | Sea of Energy | 16.4% | Kannir Belt | | Where the Black Current Ends | 9.3% | Aphotic Marsh |

Notice that the rate roughly tracks the region’s place in the route — earlier regions land at 40-55%, mid-route at 15-30%, late route at under 10%. That is the playerbase funnel, not the game getting harder.

Hidden achievements — what triggers outside the obvious pattern

A handful of achievements fire on actions that don’t look like kills or area entries. They are the easiest to miss because the game does not telegraph them:

• Curiosity Killed the Cat (~15.9%) — Drink Adrian’s Tea inside the Mirror Chamber before the effect expires. The chamber itself is scenery after a post-launch patch removed wall-climbing the mirrors, so the trigger is purely about timing the tea effect. Source pack calls out Adrian’s Tea as the trigger; see the Walkthrough for the exact ordering.
• Sacrifice (41.5%) — Defeat Infected Carbo. The fight is opt-in, not on the main route; players who skip the Carbo encounter route stay missing this one.
• This Settles My Debt — A postgame cleanup chain involving Cain and Archive progress. The source pack flags this as the most warning-heavy achievement because it sits past the Stone of Narrative and depends on the ending-state cycles. Plan for it on the second playthrough, not the first.
• Faster Than Lightning (18.1%) — Cain duel. Cain is a late-game NPC; the duel is a sub-event of his story arc, not a forced fight.

If you finish the game and a hidden entry does not fire, the Endings Explained page covers the post-epilogue state where most hidden triggers fire. Return to Shrine of Ancestors after the epilogue before assuming an achievement is impossible.

Pairing With Other Guides

• The full 51-achievement list lives in the Achievements Guide.
• Route planning for the Sanctuary tier is in Progression Route and Ability Gates.
• The speed-run and cleanest route to Sealed Spire is in the Walkthrough.
• The hidden / missable triggers past the epilogue are catalogued in Endings Explained.

If a rate looks off when you reload the page, the live rollup wins — these are snapshot numbers, not guarantees. Steam re-aggregates every few days, and an achievement you unlocked today may take 24-72 hours to register globally.

Sources: Steam Community global achievement stats (snapshot 2026-09-21), Exophase 51-achievement mirror (Steam mid-table recovery), source pack for the Adrian’s Tea trigger and the post-launch mirror patch.