http://www.writeups.org/affiche_fiche.php?id=2897

Even before she joined Sinestro Corps and got Q rings she was able to fight off GL's:

Fatality has been trained by the Warlords of Okaara - she is thus a stupendous master of armed and armed combat, and a great warrior. Her alien physiology also gives her superhuman endurance, which was in fact her main tactic against Green Lantern - fight them for hours while staying on the defensive, stalling until they exhaust their 24 hours charge.

Her main asset is her DEX - she's very hard to hit, and pretty much never misses. Being extremely fast, she can easily mount a savage assault before her opponent can react. She tends to toy with her opponents, and rarely subs Martial arts for EV - she prefers her targets to last. This doesn't apply to robots and the like, though - which, combined with her partisan's Sharpness, allowed her to ambush and kill a Superman robot in but one blow.

This strike may have been helped by Fatality's ability to see weaknesses. This ability is of unknown origin, and may be a mutation over her basic alien heritage. Weak zones appear highlighted to her eyes. This ability is rather weak, however - it is hard for her to see through ordinary clothes, and she is unlikely to roll RAPs against most opponents. She may use it just in case when ambushing someone - I suppose she actually rolled a double or two against the Superman robot, meaning even her low APs were useful.

Fatality has researched the Corps very well, and knew who each of the Lanterns was (barring secret identities and the like). After her clash with Kyle Rayner, her left arm was replaced by an artificial one made of some sort of liquid metal - although it could morph to look like her normal arm, which was the default mode. Her Terran-made other prosthetic, though, is obviously artificial and much less advanced.