A final idea now!
We're a first time group so we don't have any existing code ready (like fools we decided to make it on the spot), but it seems to be going well.
We chose an idea focusing on slimes and the quest for treasure: all true adventurers sacrifice slimes to get what they want, right?
Our concept slime:

We're working on our sprites now, and after this tileset is finished, its the end of the first night for us.