Harvest Festival

The Harvest Festival (魔王ヘの進化) occurs once all the requirements for the evolution to a True Demon Lord are met. Once it is about to begin, the Voice of the World will announce it and it will start immediately and cannot be stopped even by the one undergoing the evolution.

During the Harvest Festival, the one ascending undergoes a transformation in which they can physically and racially evolve, and gain a tremendous amount of Magicules, notably ten times as much as their previous amount. Additional abilities and Ultimate Skill can be obtained during the transformation. There is also the possibility of a significant change in personality.

Additionally, the subordinates of the one who ascends will also receive "gifts" of power or ability.

Known Harvest Festival

 * Guy Crimson's Harvest Festival
 * Milim Nava's Harvest Festival
 * Rimuru Tempest's Harvest Festival. Rimuru evolved and awakened into a True Demon Lord through using the 10,000 Souls of the invading Farmus Army. The process involved the revival of Tempest citizens including Shion, that were killed by the Farmus Kingdom's Otherworlders previously. Everyone connected to Rimuru via Soul Corridors received "gifts" which included Skills and species evolutions.