Resistance (Disgardium Book #4): LitRPG Series

The armies of the Commonwealth, the Empire and the neutral factions, all the leading players and clans of the preventers, have been summoned under the banners of Nergal the Radiant to the sands of the deadly Lakharian Desert, to wage war against a most terrible enemy of all life itself - Scyth. His supporters include not only mindless wild races, but also nightmarish monsters: the zombie guitarist Infect, the death mage Crawler and one undead warrior by the name of Bomber.