Royal Mob Takes It All

Suddenly died while working part-time in the present world. When I woke up I was standing there with a spear. What? Isn’t this the world of the f**king game I was playing yesterday? I’ve apparently been reincarnated as a royal castle guard named Gustav. Moreover, I’m a guard who is destined to die in the event that the princess is kidnapped by the Demon Lord’s army the very next day. I can’t die just after being reborn! That’s why I decided to stay up all night to level up. I thought it would be enough if I could get strong enough not to die, but I feel like I’m getting too close to beautiful girls who are supposed to be members of the hero’s harem, you know?