Hamuo 
Hell Mode (Manga): Volume 3 [EPUB ebook] 

Allen continues his Hell Mode adventure as he fights alongside the famed War Demon Zenof. Upon learning that both Zenof and Viscount Granvelle are aware of Allen’s hidden Talent, he decides to cooperate with them to defeat the monsters surrounding the city. All the while, House Granvelle is hit with devastating news about Mihai, and Cecil faces a life-changing decision. To make matters worse, she and Allen are kidnapped. When the culprit is revealed, Allen must make a choice of his own. Will the two be able to make a safe return to the Granvelle estate?