Thanks for the TL. Forgot about this manga.
This chapter emphasizes one of my beefs with it (but it's a beef with manga overall). The reckless way in which the Demon Queen (I refuse to call her Lord, that's a title reserved for a male, no I'm not going to argue with you), acts. As Wyrm said, there are many ways to deal with MC and his auto-resurrect or infinite resurrect ability to keep the Demon Queen alive.
Also, remember, she may seem invincible now, but she was DEAD meaning someone defeated her. You can't say she died of old age, else MC would've resurrected her as an elderly Demon Queen. Her and everyone else in the dungeon would be elderly.
Another one of my beefs is that out of her crew, she's been shown to be the only OP one aside from maybe the vampire girl.
I mean it makes no sense for them to resurrect a Saintess whether she was betrayed or not. They don't even think about looking into her more to see what type of person she was. The necromancer girl was 50/50 with a heavier chance of her leaning to their side considering her skillset. A Saintess is obviously going to be pro-"good." It's like they'll find out that the "Hero" is buried somewhere, the one who killed the Demon Queen and her crew and be like, "Oh, it'll be interesting to revive them and see what happens." Doesn't make sense. Why hasn't the Demon Queen taken him around the world to revive all of her old subjects to build a new army? Instead, they've just been chilling in their crypt/dungeon.