The old man (Patreon)

Most of the bar stopped to watch this game. It lasted well into the night, but in the end your bard is victorious. The old man smiles and nods curtly. "Well played, sir, enjoy the spoils of your victory". As the party celebrates, you watch the old man leave... strangely, he seems to grow a little taller outside the bar before disappearing into the trees. 

The next day after much discussion your party agrees to try the key. Interestingly, the key only seems to attach to wood. You find a large oak tree in the woods. Using the key opens the side of the tree to reveal a beautiful world beyond.