Here’s another little magic weapon I made for 5E game and yes, it’s real easy to convert this over to a OSR style game.
The Blade of Darkness is a sentient Chaotic Evil magical long sword. It does not offer any bonuses To-Hit or Damage but does count as magical to overcome a creature’s resistances. It can only communicate with its wielder empathically conveying only its pleasure or displeasure with its wielder’s actions. If it get angry enough it can attempt to take control of or influence the wielder.
Cha: 14 (+2)
Powers: Once per day, the Blade of Darkness can cast Arms of Hadar at 2nd level. (Save DC: 13).
When the Blade of Darkness slays a living creature roll 2d6. If the total is 2 or 12 then the slain creature returns as zombie (under no one’s control) at the beginning of the next round. On any other result, the wielder gains that many temporary Hit Points.
Artwork by Daniel F. Walthall and used under a Creative Commons License.