If a character is dead, and a resurrection is attempted by a spell or spell effect with longer than a 1 action casting time, a Resurrection Challenge is initiated. Up to 3 members of the adventuring party can offer to contribute to the ritual via a Contribution Skill Check. The DM asks them each to make a skill check based on their form of contribution, with the DC of the check adjusting to how helpful/impactful the DM feels the contribution would be.
For example, praying to the god of the devout, fallen character may require an Intelligence (Religion) check at an easy to medium difficulty, where loudly demanding the soul of the fallen to return from the aether may require a Charisma (Intimidation) check at a very hard or nearly impossible difficulty. Advantage and disadvantage can apply here based on how perfect, or off base, the contribution offered is.
After all contributions are completed, the DM then rolls a single, final Resurrection success check with no modifier. The base DC for the final resurrection check is 10, increasing by 3 for each previous successful resurrection the character has undergone (signifying the slow erosion of the soul’s connection to this world). For each successful contribution skill check, this DC is decreased by 3, whereas each failed contribution skill check increases the DC by 2.
Upon a successful resurrection check, the player’s soul (should it be willing) will be returned to the body, and the ritual succeeded. On a failed check, the soul does not return and the character is lost.