Overlord: Sei Oukoku-hen

A continuation of the fourth season, this film adapts the "Holy Kingdom" arc. After twelve years of playing an MMORPG, Momonga logs in to discover he is trapped within the game world permanently. Over time, his character rises to become Sorcerer King Ains Ooal Gown. The Sacred Kingdom, once thriving, is now nearly destroyed but had long remained peaceful due to a massive wall preventing invasions. This peace ends when the Demon Emperor Jaldabaoth attacks with a force of demi-humans. The Slane Theocracy, fearing their own invasion, seeks aid from the Sorcerer Kingdom. Ains Ooal Gown responds by uniting his undead forces with the Sacred Kingdom and Slane Theocracy to confront the Demon Emperor.