Castle of champions

Iron Builder is back! It seems no one can beat the Mayos, but now their days in the arena are past and it may be time for a new champion to take their place. Defending IB 6kyubi6 seems to have built a place of residence for whoever emerges victorious in this round, which you can follow on Flickr here. 

The seed part for this round is the pitchfork element, and 6kyubi6's challenger is vitroleum. 

(By the way, I love those miniature cannons!)