How far can Kozu go?

I never see Kozu mentioned in rankings of the strongest Ninjago villains, even though he is extremely powerful. He has immense physical strength, is nearly indestructible, and possesses truly prodigious power. On top of that, he is the original right-hand man of the Overlord. Lloyd’s powers were completely ineffective against the giant Stone Warrior, and even with the four ninjas, Lloyd couldn’t do anything except rely on strategy to trap him. Since Kozu is the general, he should be even...