The Demolisher Cannon was rented to Queen Mary Anne Towant’s kingdom by the crew of the Glomar as a mining tool but in episode 9 the Glomar is passing through town and sees that the queen has broken the terms of the rental agreement by threatening the dissidents in her kingdom with it. The Glomar’s crew steal the cannon back and mount it on the Glomar. The powerful energy cannon is a big help to them as they try to evade Chiram forces.
NOTE Many English speaking fans know this weapon by the name Hasai Cannon. Demolisher Cannon is a direct translation of its name.