Thanks for the chapter!
He's not a Demon King since his class under Analyse is Monster Tamer. Although might be one of those jobs that can be earned a certain way like a swordsman getting the job Knight after being knighted by a King for example. After all, that Tome can't be the only way to change jobs, just probably the only surefire way for the unique or ultra rare ones like Hero or Pope. Would be really funny if Ruri had her job changed from maid to Demon King from the Tome at the same time as his job changed. Would explain why it lit up and was destroyed after she touched it while he was holding it. Guess will have to wait for her to be analysed to find out for sure one way or another. Also, would be funny if dragon turned out to be female and could transform into a beautiful human or elf form. For Marin's sake hope she tries to recruit him and finds out Tome is destroyed before taking another party down. Although why doesn't she go with a large party of clerics, holy knights, and paladins? Granted Pope wants to keep using Tome on his son a secret but could just order the party to keep mouths shut and have her act surprised when happen across Tome like Pope was given a vision to have a great item retrieved from bottom of dungeon but only knew it was there but not what it was or something like that.
@Liquidxlax Being a Demon King doesn't mean she can talk to any monster out there. MC can do it due to new skill received when tamed wolf, but Ruri can't. Although not sure what are considered demons in that world, but if it's a race like elves or dwarves she'd be able to command and talk to them, but not all monsters. Then again, depends on what's considered a demon like can she command any monster classified as a demon like a succubus, goblin, imp etc. but not non-demonic monsters like slime, harpies, giants, etc.? If she was a Monster King she should be able to talk to any monster like MC.