Invaders of the Rokujouma!? 20

From Author Wars - https://authorwars.com/books/invaders-of-the-rokujouma-20-2569382.html

Overview:

Title: Invaders of the Rokujouma!? 20
Author: Takehaya
Year: 2019
Type: Novels

Editions/Publications:

2019 . Invaders of the Rokujouma!? 20 (2019, Takehaya, J-Novel Club, ISBN-10: 9781718312425, $6.99, pages, ebook, Novel)
2021 . Invaders of the Rokujouma!? Collector's Edition 7 (2021, Takehaya, J-Novel Club, ISBN-10: 9781718308367, $29.99, 600 pages, Trade Paperback, Omnibus)