A mindless unstoppable machine of destruction. The Juggernaut obliterates any army that tries to stop him.
The Juggernaut doesn't have much going for him beyond being a construct while his minions, unique to his fight, can be spawned via cluster bombs anywhere on the map that isn't past the 3 Imperial Guards at the top, with decent stats going for them. He has one particular key problem: well-upgraded Paladins can put him in a melee lock loop. The Juggernaut does have an area attack and a long-range missile launcher, but they don't do enough damage to wreck the Paladins a bit faster. This isn't too bad, though, because he's the first boss. He's supposed to be a little easy, though still there to make sure that you understand how vital it is to tear through enemies' HP.
The Juggernaut enters the map from the right, so concentrate your towers in this area.
Make sure that you have towers near the top of the map. The Juggernaut's Golem Heads often spawn very close to the castle. Using Arcane Wizards with teleport is also a good tactic to stall Golem Heads, as they can send all of them back in the path.
Whenever you get the chance, place reinforcements near the Juggernaut. Even if he destroys them with one strike, the reinforcements will slow him down.
If you use Malik Hammerfury, he is useless in the golem heads, so put him to the Juggernaut. The Juggernaut will kill Malik in min.3 hits depending on what level he is.
The 500mm Big Bertha's special abilities Dragonbreath Launcher and Cluster Missile Xtreme operate very similarly to the Juggernaut's weapons, implying that it was the result of reverse engineering the Juggernaut.