The trolls finally finished their session. Having faced all this hardship they could now finally claim their reward. They had done it. At the same time the kids just started their session, ready to go on their adventure and create their own new world.
But things didn't go as planned.
On the moment when the kids entered and the trolls got ready to open the door to their new world, things glitches, and everything got merged.
Now elements from both worlds have manifested themselves into this new world the trolls had initially created, their memories of their session erased.
It was as if trolls and humans have always lived together, for as long as they can possibly remember. This is how it's always been. While in the past their races have had difficulties, they now manage to live side by side in what you might be able to consider as perfect harmony.
Among the things that manifested themselves here, magic had been one thing, and has grown out to have become a very important part of their society. While hidden from those who do not posses this magical ability, many witches and wizards both among trolls and humans alike have passed on their knowledge to their offspring.