Keepsakes can sometimes mean all the difference in Hades, as they provide Zagreus with powerful effects that can either make him stronger or help the player control what boons they get. Each of the Cthonic gods in the Underworld have one, and so do all of the Olympian gods. Even Sisyphus and Cerberus have keepsakes that the player can get, but many players are still missing the keepsake of Hades himself.
In order to get a keepsake from a character, the player needs to gift that character a Nectar. In most cases, the first nectar given to the character will result in them trading their keepsake to the player, but this isn't true for Hades. In his case, there are some steps that need to be completed before Hades players can get their father's keepsake.
This is one of two keepsakes that aren't available until after the player finishes the main story. Without spoiling anything, it will be very clear when that happens, as Zagreus' main goal will be completed. After the series of cutscenes that play when the player beats the game, Hades can then be given more nectar.
During the story, players can give Hades a nectar but he won't accept any more than that one. It isn't until the player has completed 10 successful escape attempts that the story will be complete and Hades can be gifted more Nectar. From here, the only thing left to do is give gifts to Hades until two hearts of affinity are filled. This is still somewhat time consuming to do, as Hades is frequently out of the house or having conversations with other residents instead.
Once the player gets Hades' Keepsake, the Sigil of the Dead, equipping it sets the player's call to Hades' Aid. Using this ability in combat causes Zagreus to go invisible briefly (much like the Hades boss fight) and deal bonus damage on the next attack. Additionally, the keepsake makes the god gauge start with some charge (10% per level). Using the fully charged call will make the invisibility last much longer, and Zagreus won't become visible after an attack, instead remaining concealed until the time runs out.
Players cannot have Hades' keepsake equipped and get another call from a god during a run. If the player tries to switch to Hades' keepsake but already has a call, they will be required to sell before equipping the keepsake. It may take some time for players to get 10 successful escape attempts, but Hades rewards perseverance.
Hades is available now on PC and Switch.