Almost every boss will become 'Shocked' and skip their turn in SMT 1 if the Heroine uses her Zio skills. You can use this to stunlock (nearly) every boss including the final bosses.
In SMT 2, offensive magic is worthless and guns are the only things that deal any damage until you start to gather the Pillars to go to the Abyss. Then you will switch over to your swords while having a party of demons using nothing but the insanely overpowered -kaja moves every single turn while occasionally casting a full party heal.
Don't sex the Hiroko...