I have just finished Volume 13, all I can say is if you really love Overlord then I suggest you read the light novels. The paladins of the Holy Kingdom Arc is
Amazon.com: Overlord, Vol. 6 (light novel): The Men of the Kingdom Part II eBook : Maruyama, Kugane: Kindle Store
Overlord Vol. 1 - Manga Review — Taykobon
Overlord, Vol. 2 (light novel): The Dark Warrior (Hardcover) | Tattered Cover Book Store
I've watched the Anime, read the Light Novel and now re-reading the Manga on it's latest chapters, THIS SCENE still gives me GOOSEBUMPS every time. That's how you know how great Overlord