And what prevented you from reviving the other characters? Tonberry isn't exactly the quickest enemy in the world, you normally have bags of time in between attacks.
To answer your question, inflicting him with STOP and POISON work wonders, and then bash away with stong magic, double cut and summons. Simple (if a bit time consuming, hence poison to speed things up).
Its okay to be jealous, I am this damn good. GT - Sniper Fox29.
If memory serves me correcly, MT has 44,444 HP and an attack that does damage based on the number of kills that character has (Everyone's grudge) and one instant kill (knife). If you have it, KotR works wonders. Other than that, slow and stop work. Double-/4x-cut are good. Poison.
If you have Morph, you can morph them for a Ribbon.
.-*-._.-*-gmorris7897-*-._.-*-. *-.-***-.-***************-.-***-.-* - Freedom isn't free. Freedom costs a buck-o-five.
You may not want to attack too fast. Everyone's Grudge is used when you attack twice during one of their turns, so if that's what's killing you then just throwing everything at it isn't always a good idea. The knife is just an instant death attack, get some Death protection and you can take your time.
"People demand freedom of speech to make up for the freedom of thought which they avoid" ~ Soren Aabye Kierkegaard
Safety Bit accessory or Added Effect=Destruct materia work well to prevent Chef's Knife. Everyone's Grudge, however, is a different beast altogether. It's not an easy fight, to be sure, but Stop/Poison abuse is the best way to go, typically speaking. Or just Omnislash/Highwind/Doom of the Living/Ultimate End him to oblivion.
I'm a girl, damn it! I wanna do girly things! Like fix up someone's hair and get phone calls expressing romantic sentiments!