Books in the RE: Monster series

WAR IS BUSINESS AND BUSINESS IS GOOD! Apo-Rou has successfully beaten back the coup attempt and gathered a group of orphaned children to form the youth training unit Sol-Child! And his next project--the founding of a trading company and the construction of a department store in the capital!! In order to improve his own abilities, Apo-Rou has also decided to take on a legendary dungeon...solo! In a nest swarming with demons, a fierce battle between powerful opponents unfolds! Will Apo-Rou live to see his retail dreams come true?!