Sybil

Source coverage: 1 independent source, Miraheze Sybil; checked 3 November 2026. Empty cells mean the referenced table does not supply that field.

On Explorer you can save from the menu. On the harder difficulties the public gameplay page says you fill the Danger meter and talk to Sybil when she appears in the wall. Cursed mode asks for the second notch, not the first. A free save also shows up at 4:00 a.m. I put the full difficulty split on the saving guide so this page can stay about her.

The same article calls her the founder of the astronomers and the person who made the planetary discs and the puzzle doors. That is why the disc page and her page keep citing each other. She looked at the Visitor before anyone else in the building, then, the biography says, she wiped her own memory on purpose.

There is a boss fight. The wiki describes organs you destroy while other enemies appear. I am not printing a phase chart, because a single elemental weakness is not published. Patch 2.3 added new save conversations, a new theme for the fight, and a line on the boss counter. Those are version notes, not a new identity.

Perfect Ritual, the Final True Ending, and Unity all name her in the ending conditions. Jasper, Beryl, Aster, and Aurelius are the other astronomers on her related list. Aster can join the party. She cannot.

If you are hunting the key that players call “Sybil’s key,” the key index is the place that separates it from the janitor ring and the iris keys. I will not guess which door it opens beyond what that table already quotes.