You can use a bonus action to prime the stakedriver and charge the runes found on the blade, while your weapon is charged your next attack deals an additional 2d6 radiant damage and if the target is Large or smaller must make a Constitution saving throw or be knocked 5ft away from you. You can use this ability a number of times equal to your proficiency bonus per long rest.

The stakedriver deals an extra 1d6 radiant damage on a hit. In addition, aberrations have disadvantage on the saving throw to be knocked away by this weapon.

Proficiency with a Rapier allows you to add your proficiency bonus to the attack roll for any attack you make with it.

Notes: Bonus: Magic, Damage: Radiant, Cleric, Damage, Combat, Finesse, Vex