Moonsilver Blade
The Moonsilver Blade was a sword owned by the Primarch Sanguinius and was highly effective against Daemons. He used the Blade as a backup weapon alongside the Spear of Telesto, during the Horus Heresy.[1]
The Moonsilver Blade was said to have been granted to Sanguinius by Rogal Dorn and was built from the same alloy as the frame of the Phalanx.[2]