If Edge has two weapons equipped, the damage he deals from the Attack command is equal to the attack power of his left weapon plus the attack power of the right weapon plus Edge's Strength divided by 4, added together with Edge's Level divided by 4, multiplied by 2.
$ Base Attack Power = Weapon on Left Hand's Attack Power + Weapon on Right Hand's Attack Power + (Str/4 + Level/4)*2 $
However, if Edge is only equipped with one weapon, the damage he deals from the Attack command is equal to just the attack power of the weapon.
$ Base Attack Power = Weapon's Attack Power $
After calculating the base attack power for a physical attack, several modifiers are brought into play, such as Critical Hits, elements, and status effects.
Edge's Throw command allows him to throw weapons at his opponents for high damage. His Steal allows him to steal items from his opponents and Ninjutsu allows him to cast special Ninja spells. In the Advance and Final Fantasy IV: The Complete Collection releases, Edge gains the Hanzo Gloves for completing his Lunar Trial that upgrades Steal to Plunder. With Plunder, Edge will attack if he successfully steals. In all 2D versions of the game, Edge takes some damage if he fails to steal an item. In the 3D releases Edge learns more Ninjutsu skills.
Edge and the Eblan Four have a level cap of 40 in his chapter. Edge has all around decent stats with the exception of his low Spirit, and while he is primarily a physical attacker he can be a somewhat effective Black Mage with Ninjutsu. Edge's greatest asset is his high Speed, and he is the second-fastest character in the game after Tsukinowa.
Edge retains his Ninjutsu techniques, and learns a much larger variety of them than his apprentices do. He also has the Throw ability and Mug (Smash & Grab in the WiiWare version), which lets him attack enemies and attempt to steal from them.
His equipment has expanded in Final Fantasy IV: The After Years. The most significant item is Rubicante's cloak, the Fire Scarf. It provides adequate Defense and can absorb all Fire-elemental attacks and when combined with a Protect Ring can give him absorption to Ice and Lightning additionally.