At the Holy Palace you recall Deserters and revive dead soldiers that became Souls (distinct from the Hospital's wounded/SvS dead). Higher level increases deserter/soul capacity, horn production speed, and the dead-to-soul conversion rate. Buildable at Keep 11. The Holy Palace must be raised first to raise the Keep to 38 or to build/raise the Victory Column. All menus stay usable during upgrade (soul revival and deserter recall keep working). Milestones: Lv25 unlocks Troop Soul Revival (ability to revive souls); Lv35 Duty Officer (increases max deserter capacity and war-dead-to-soul conversion rate, and decreases resources needed to revive souls; ideal Helena, then Trivia Hecate). Soul revival consumes Soul Crystals (separate guide). Keep-gated 1:1, cost F/L/S/O, speed to +610% by Lv50, Power ~107M at Lv50. For a bot, the two automatable actions are recalling deserters and reviving souls, both gated by capacity that scales with level plus duty officer; both count toward some events (Dawn of Civilization, Alliance Competition).
Original research source: Evony Guide Wiki