Hello Penguins! Here are the cheats to the 3rd and last Medieval Quest (I had to complete it on a French server, because on the English server it won't load)
1) Enter the third gate that says "Quest 3"
2) You will now be in the first challenge. To win, you have to find the marble that CP chooses under the moving cups. Once you find that 3 times, you will move on to the Second Challenge.
3) The second challenge is a bit harder. You have to navigate across the room, clicking buttons to make the walls go up and down. My room was completed by clicking Red, Blue, and then Yellow. (I don't know if it changes for everyone) Also, make sure to get the free hat!
4) Now this room shows directions to complete the last challenge. (Make sure to get the free shield...and wear it!)
5) And now the last challenge. To beat the Yellow dragon, you have to wear the white/yellow knight's shield. When he breathes fire on you, it shoots back to him. To beat the Red dragon, you have to throw snowballs at it. And to beat the blue dragon, you have to throw snowballs at the bucket above his head filled with lava, to make it fall on him.
6) After you finish the dragons, you will be moved on to the last room. (Make sure to get the free item!) You have now completed the 3rd Quest!
Here's a video guide also, just in case you would rather use that :)