In the end, things happened the same way Ryan had said. There was a big monster waiting for them at the end of the dungeon, and when Ryan killed the monster, they obtained access to a treasure chest that gave them the chance to choose a class. Although the classes available weren't that impressive, it was much better than nothing since Katelyn and the kids didn't have a single class.
Congratulations! You have cleared the dungeon and obtained its treasure! As a reward for your achievement, you can obtain one of the three following classes: Viking, Rogue, and Teacher.
Please be aware that clearing this dungeon again won't give you the chance to unlock the other remaining classes. If you want to obtain them, you will have to search for those in other dungeons.
"Again… not a single new class. Regardless, this is a good opportunity to test this system even further."