I just got chrono Trigger and im Hooked

Well i got it, but ive already experienced a tragedy related to it...i played nonstop up to beating Magus, died due to arrogance and got sent all the way back to the jet bike scene...tragic right? But anyway can someone tell me when ill unlock Magus once i get back to that part?

You dont really *unlock* him. Depending on what you do in the game, you will meet Magus somewhere in the 12000 B.C. era after you destroy the Black Bird and you will have a choice to either fight him or not to, if you say no to fighting him, then he will become apart of your team, if you fight and beat him, well you lose him since you pretty much kill him. XD