On the rare occasion a Squat lives beyond his normal lifespan of 300 years, he develops psychic abilities that enable him to provide expert insights to his commanders.
A Questor Titan is well equipped to take down large numbers of enemy units with each volley it fires. Its Castigator Cannons are especially good at cutting through swathes of infantry.
Cannons of Khorne (aka Hellfire Cannons) are built with the sole purpose of destroying heavily armoured targets at range. They should be deployed at a location with a good field of view before the battle begins in order to maximise their potential.