Requirements
- Defeat Scylla and the Sirens at least once.
- Unlock all of these weapons: Sister Blades.
- Requires all of these story events: accept Poseidon's first boon.
- Requires The Sorceress revealed.
- Requires The Wayward Son revealed.
- Requires The Furies revealed.
- Requires Persistence revealed.
- Requires Death revealed.