I really need help defeating Naraku

Which time? for if it is the first time (In the Castle Tower) you face Naraku you have to lose Naraku kills you all in one attack. The second time is on the island you must be patient use Miroku's spiritual vision to see how much HP Naraku has and take your time. The third time on the way back to Kururugi Village Naraku's HP is ???? unknown you just have to be carsful and patient it may take a while after all it is the final fight of the game. Use energy wisely. It took 13 minutes to beat him I thought it was never going to end but it with time. Hope I was able to help you with your question.

For the final battle, I was playing the female character the first time around, and she has a really useful "heal all" tech that came in handy against Naraku's attacks. Just concentrate on having as many characters as you need keeping your team's HP up, then have the rest of them perform co-op techniques, because every time Naraku hits you, it will re-fill your energy meters so that you can keep going.