Volume 7 (Light Novel)

Synopsis
I’M SORRY.

''Feeling ill-prepared for the looming battle against his former pupil, Seiya returns to the underworld to acquire some new skills. But every boon gained from this realm comes at a cost—Rista’s dignity. First, his group hones their stealth abilities by learning invisibility magic. Then, Seiya ventures to the Infinite Corridor to harness the powers of darkness! They’ll need more than a couple new tricks to defeat Mash, the Dragon Lord, though. To gain an edge in the fight to come, they will have to peer into the past and learn the tragic origins of Warped Gaeabrande…''

Chapters

 * Chapter 21 : Rosalie's Resolution
 * Chapter 22 : Monster Hero
 * Chapter 23 : A Teat's Worth
 * Chapter 24 : A Borderline Invisible Goddess
 * Chapter 25 : To the Nakashi Vllage Ruins
 * Chapter 26 : Out of Control
 * Chapter 27 : The Power of the Holy Sword
 * Chapter 28 : Wraith
 * Chapter 29 : Mash's Weakness
 * Chapter 30 : A Goddess of Character
 * Chapter 31 : Into the Darkness
 * Chapter 32 : The Emperor Dragon
 * Chapter 33 : A Hopeless Love
 * Chapter 34 : Propaganda
 * Chapter 35 : Divinity
 * Chapter 36 : Memories of the Soul
 * Chapter 37 : Master and Pupil
 * Chapter 38 : Rightfully Yours

Leading

 * Seiya Ryuuguuin
 * Ristarte
 * Cerceus
 * Rosalie Roseguard

Newly introduced

 * Great Mother of Dragons
 * Marionelda
 * Mash Dragonight
 * Natosus
 * Slauri