Chthonic Keys are one of several currencies that can be earned within the Underworld. Along with Diamonds, they are available as bounties to whoever can defeat the guardians of Tartarus, Asphodel, Elysium, or Styx. They can be used to unlock additional Aspects of Zagreus' weapons, as well as some options on the Mirror.
Codex entry[edit | edit source]
Obtaining Chthonic Keys[edit | edit source]
Chthonic Keys can be obtained by defeating the Furies, the Hydra, Theseus and Asterius, and Hades while playing at or above the Heat threshold listed on the Pact. They can only be earned once per boss, per weapon, per Heat level.
Occasionally, a Chthonic Key can also be purchased from Charon's shop in Styx for 1500 .