Kanata Yanagino 
The Faraway Paladin (Manga) Volume 11 [EPUB ebook] 

The time has come to avenge the people of the Iron Country!
Will and his allies have reached the Rust Mountains at last. Together they make their way to the Rock Hall, meeting those who stayed behind to defend their home while the rest of the dwarves fled to safety. It’s time for Al to step up as the descendant of Aurvangr, king of the dwarves, to see their souls off into the beyond.

When our party reaches the throne room, they’re confronted with a Scarabeus, who’s claimed the dwarf crown for itself. A fierce battle begins between those who have conquered the Rust Mountains and those who have come to reclaim it.