Overlord (Season 3)

Synopsis:
At the Katze Plains, Ainz asks of Gazef if he is indeed serious; the Royal Head Warrior is. Both know Gazef will die, and while Ainz as an enemy combatant is within his reach, the fact that gazef cannot react to a missed tentacle strike by a Dark Young shows a devastating difference in power. Even as Gazef still wants a duel, Ainz wonders if this is because he allowed Gazef to live. Gazef states it is out of duty and honor to Re-Estize that he fight Ainz. So after much assurance, Ainz as a collector finds it a waste to kill a warrior of his rare caliber, and accepts Gazef's formal challenge for a duel.
Living an ordinary high school life in Tokyo during the day, the group maneuvers the metropolitan city as Phantom Thieves after hours. Let the curtain rise for this grand, picaresque story!