Revival
Revival is how a player character returns after death. Death is permanent for every NPC in Valdaria, and the player alone can come back, through the Absence of Soul they carry.
Dying first
Dropping to zero health puts you in a dying state rather than killing you outright, and allies have a few turns to stabilize you before you bleed out, as described on Combat. While you are dying you can also choose to give up on the spot, at no credit cost, instead of playing out the remaining turns.
After death
Death shows a recap of how it happened, followed by your revive options, whether you bled out, gave up, or were struck down outright. Revival is available to every player, free and paid alike.
A revived character returns after a substantial wait of game time, so death removes you from the current fight but not from the campaign. Fallen party companions return the same way, as described on Party.
Your nemesis
The enemy that killed you is permanently marked as your nemesis, and the world treats them accordingly from then on.