Berserkers, wielding dual axes, charge very rapidly headlong into battle. With paper-thin defenses, melee range and no self-buffing skills they will usually leave their army behind and get shot to bits before they can do anything themselves.
However, every skill they have boosts the damage output of their troops, typically of the same race as themselves. If you equip Relics that completely ignore the Titan themself and focus entirely on ones that boost the relevant Troop you can have a very powerful army. One particular noteworthy combo is a high-grade Mossmane Titan with an entire army filled with Panthers defending your castle, packed with relics that boost the Panthers. The Panthers can nearly keep up with the Titan in movement, and at roughly equal upgrade levels any attacker seeing that kind of army pounding towards them is bound to get genuinely frightened.