I guess they're Emerald and Ruby? Maybe more?
I never found much satisfaction with FF7, and I quit it when I beat Sephiroth, but I did spend a lot of time trying to kill the green robot thing, prolly Emerald Weapon, that was underwater.
I suppose I'd have to level my characters to max, which seems completely unnecessary. I can't remember exactly how badass I was, but I know Sephiroth was easy, so I was obviously powerful enough to beat the game yet absurdly weak vs. the Weapons enemies.

So why bother? What is the reward for beating them, should I decide to dust off the game for another play (or check the memory card), spend hours leveling, and then maybe, hopefully, somehow, actually beat the thing?

Or was I going about it wrong, making the fight a lot harder than it needs to be?

Or should I just research this on the internet somewhere?

Maybe somebody could just tell me in spoiler tags so I don't have to play the game again.