Pact blade

Pact blades were weapons that could also serve as a warlock's spell focus. This versatility meant that they were a preferred and much-sought-after implement among warlocks.

Description
A pact blade was typically a dagger, but could be any lightweight bladed weapon, such as a sickle. Although they were valued both as wickedly sharp blades and as useful spellcasting implements, they were somewhat awkward to wield in battle when also being used as spellcasting foci.

Some pact blades were said to be so suffused with the energies of the warlock patron to which they were bonded that they could confer feelings, sensations, and even powers associated with that patron onto the wielder.

Powers
As magical weapons, pact blades were more accurate and more devastating than ordinary blades, especially when a target was struck in a vital area.

As an implement for assisting with warlock spellcasting, pact blades conferred greater potency to spells, invocations, and other warlock powers. They could also be used to confer a curse onto a warlock's foes: if a cursed individual attempted to strike the warlock, they were punished by receiving a magical wound as if they had been slashed by the pact blade.

The more potent the enchantment of a pact blade, the more powerful were both its deadliness as a weapon and its usefulness as a spellcasting focus.

History
Pact blades were said to have been in use since ancient times and across all corners of Faerûn, from Netheril in the north to Chult in the south, and from Waterdeep in the west to Mulhorand in the east.

They were favored and highly desirable among warlocks as of the late 15 century DR, however even minor pact blades could require money and influence to acquire. They were known to be available in Baldur's Gate, Neverwinter, New Velar, and Suzail.