When fighting through the first ruins towards the Seal of Fire, it is recommended that you get to at least level 13 for each character. If not, the battle with the Boss will either require an absolutely brilliant strategy or result in the death of your
party. Also, make sure that Genis has his skills set to only Aqua Edge and/or Icicle if you have obtained that skill; otherwise he will waste TP using skills that will cause very little damage for the cost.