Sentient Weapons: A Basic Fantasy RPG Supplement

From the Introduction:

This supplement provides information for Sentient Weapons, a special type of magic item, under the Basic Fantasy Role-Playing Game rule system.

Some magic weapons have an intelligence all their own. Only weapons proper (i.e. not ammunition) will be intelligent, and it is unusual for a sentient weapon to be smaller than a shortsword. These weapons think and feel the same way characters do and should be treated much like NPCs. Sentient weapons have extra abilities and sometimes extraordinary powers and special purposes. In general, less than 1% of eligible magic weapons have intelligence; it is recommended that the GM place each one specially, and not give them out as part of randomly generated treasures.