The Blades skill covers the usage and maintenance of standard bladed weapons (p. 334).
A player uses their Blades skill whenever attacking with a blade weapon in melee combat (p. 191, EP). Blades may also be used for tests involving maintenance of the weapon, but not for repairing or modifying the weapon (that would be Hardware: Armorer skill). This skill is used for blade weapons implanted in the body at the end of an appendage (hands, forearms, feet, octomorph arms, etc.), but the Exotic Melee Weapon skill is used for blades implanted in other parts of the body.
Example (optional) specializations include Axes, Implant Blades, Knives, Swords.