Could someone tell me what level I should be to beat the boss in the Zanarkand Ruins on chapter one?
Hmmm i guess as high as possible? 
he isn’t that hard, with the three standard jobs
(Thief, Gunner and Warrior) or a white mage he should be no problem.
Ok, I’ll keep pain on warrior, and Rikku on White Mage, then Yuna can be Gunner.
Not hard at all. In fact I had all level three spells with Yuna, and a couple of shots and he was dead. I forget which spell I used though.
I hardly used spells, In fact i completed the game with Fighters, i started to use mages after I completed the game once.
I need to train more then, he keeps killing me with this one attack that he uses when he’s almost dead.
Which meansd you almost killed him, keep going.
Damocles Photon? That attack is pretty mean.
Try this; keep one person on standby while everyone else keeps attacking to lower the boss’s HP. When you’re a few hits away from getting the boss down to critical, have the standby character begin casting a high-level spell. By the time the boss starts to set up Damocles Photon, you’ll have killed him.
If that doesn’t work, then simply just keep selecting Attack with Paine (Warrior) and Rikku (Thief), while having Yuna use Trigger Happy. The key to defeating most enemies in FFX-2 is to simply overwhelm them with attacks to hold them off.
Yeah, that. And, thanks!
Any body need help beating trema in the via infinito lv.100