Kugane Maruyama books in order
17 books in the catalogue, about 93 hours of reading in all; the shortest takes 4 hours and the longest 7 hours.
1 series and 1 standalone book in the catalogue.
Overlord
18 books 1 
The Undead King 4.8 h 
The Dark Warrior 4.8 h 
The Bloody Valkyrie 5.4 h The Lizard Man Heroes 5.7 h The Men of the Kingdom Part I 5.0 h 
The Invaders of the Great Tomb 5.4 h The Men of the Kingdom Part II 5.6 h 
The Two Leaders 5.1 h 
The Caster of Destruction 6.0 h 
The Dwarven Crafter 6.3 h 
The Ruler of Conspiracy 6.2 h 
The Paladin of the Sacred Kingdom Part I 5.4 h 
The Paladin of the Sacred Kingdom Part II 7.5 h 
The Witch of the Doomed Kingdom 7.2 h 
The Half-Elf Demigod Part I 4.5 h The Half-Elf Demigod Part II 4.5 h
The Undead King 4.8 h The Dark Warrior 4.8 h The Bloody Valkyrie 5.4 h The Lizard Man Heroes 5.7 h The Men of the Kingdom Part I 5.0 h The Invaders of the Great Tomb 5.4 h The Men of the Kingdom Part II 5.6 h The Two Leaders 5.1 h The Caster of Destruction 6.0 h The Dwarven Crafter 6.3 h The Ruler of Conspiracy 6.2 h The Paladin of the Sacred Kingdom Part I 5.4 h The Paladin of the Sacred Kingdom Part II 7.5 h The Witch of the Doomed Kingdom 7.2 h The Half-Elf Demigod Part I 4.5 h The Half-Elf Demigod Part II 4.5 h Overlord volume 17 length not known
Overlord volume 18 length not known