7th Saga was for the SNES.
As for hardest boss, I play mostly RPGs, so I don't have that much knowledge of stuff outside of em. So I'm gonna have to say either the Dragon Lord from Dragon Quest (Warrior) 1, or Gahleon (sp?) from Lunar: Silver Star Story Complete. Gahleon isn't that bad, I suppose, but try beating him at a low level without that stupid energy reducing ring . . . 1 and a half hours and I think he was still at full life because of that @(*@ drain life from all party members / Recover life spell . . .