Three months after the defeat of Damon Crow, Corusa Industries was attacked by an invading swarm of alien creatures. Though the recently mass-produced Kerykeion Mark III could stand against the weaker varieties one-on-one, the stronger aliens were overwhelmingly powerful. Finally, a shot struck and destroyed the top portion of the Head Office Building, which had already been abandoned save for the CEO. He was thought dead, until a new AT deployed from the basement hangar. Armed with weapons of a caliber never-before-seen on an AT, it began to turn the tide of the battle. Soon realizing the unit, whose callsign identified it as Grand Cannon, lacked melee options, some opponents attempted to engage it at close range, only for the mech to transform and reveal its true identity as the king of Advanced Troopers, Grand Kerykeion.
As Grand Cannon, the unit is designed for long-range assault, with its twin hyper particle cannons giving it enough raw power to vaporize enemies from miles away. Its left arm carries a high-performance beam rifle for mid-range assault, and it mounts the quad beam submachine guns present on all ATs. Unlike its predecessors, Grand Cannon's submachine guns have been enhanced to have the power of medium beam rifles, while maintaining the rate of fire of a typical submachine gun. However, it lacks close-range capabilities and is quite sluggish, as all of its enormous reactor output is devoted to powering its array of weaponry.
As Grand Kerykeion, the unit becomes more well-balanced, with the shoulder cannons converting into wings and the rifle into a shield capable of projecting a large and powerful barrier. With much more of its enormous power diverted to the newly-revealed thrusters, Grand Kerykeion's speed is absolutely incredible. Its armblade is derived from that of the Kerykeion Mark II, but is far superior in cutting power and can serve as a focus for a more powerful energy-laced slash. This version of the blade is also capable of penetrating energy fields.
The source of the unit's incredible power lies in its reactor - it has not one but two Baryonic Drives, their output synchronized to deliver a constant and enormous stream of power. The drives, like Pheora's, utilize the byproduct of the reaction to reduce the unit's mass and serve as propellant - the output cones of the drives are located on the back of each forearm.
Due to its complexity of operation, Grand Cannon was never mass-produced, instead serving as Ian's personal unit and a testbed for technologies that would be implemented in the next generation of ATs.
Quoting Solus Maximus
The wings to cannon look very freedom-gundam or gundam x-ish.
The inspiration for this implementation came fairly straight from the Double Satellite Cannon, actually. The rest of the armor was built around complementing that - I wanted it to look like a tank in one form, and a regal version of the Kerykeion in the other.
Believe it or not, the shield here is actually an evolved version of one that was designed nearly a year ago for the very first Kerykeion. The round plate serves to cover the internal structure and provide it with some width without making the thing too bulky. I'd have liked to have been able to store two Fangs in the shield, but it just didn't have the space. Maybe next time.
I told you this would be the big one, didn't I? Grand Cannon is the product of about a month's work to find a transformation system that worked properly. A special thanks goes to /toy/ for giving me conceptual support and some ideas that will go into the next set of models. And nope, this story's not done yet - the real part's just getting started.