Originally posted by Blathnaid

It's really simple though. Tonberry has to take it's time before it can get close enough to use 'Knife' (that's what all the walking around is). The closer it gets, the closer you are to death. And since he is immune to most devastating status effects, he seems invincible. To take him out effectively, you need to hit him multiple times in one attack. KOTR or 4xCut is perfect for this (though KOTR takes a long time to obtain). I usually wear an accessory that gives me haste which is also extreamly effective. Sometimes giving you two attacks before he can even walk forward.

Oh, and watch out. He could easily use an attack called 'Everyone's Grudge' on you that pays back the damage he recieved from that character (built up over time).
so THAT'S how Tonberry's attacks work. was WONDERING what was behind Everyone's Grudge....

now, i'd been using Haste on Cloud, but hey, in the future, i'm going to have KOTR and will try that. say, can Death Force prevent "Knife", or not?