How to Build a Dungeon: Book of the Demon King manga volume 7 features story by Yakan Warau and art by Toshimasa Komiya.

The Demon Lord Aur’s army is poised to attack the Great Sage Melissand. The Sage controls the souls of dead adventurers known as the Seven Heroic Spirits, and sends the shade of Yunis–who once lived with Aur–to raid the dungeon. She arrives on the eve of the battle, just in time for Aur’s latest bacchanal with all his minions!