Onikiri, Demon Cutter

Weapon (any sword), rare (requires attunement)
  This magic weapon has 5 charges and regains expended 1d4 + 1 charges daily at dawn. You can cast the light cantrip on the blade at will.
  Radiant Wrath. As a bonus action while holding the blade, you can expend 1 charge to imbue it with crackling radiant energy until the end of your next turn. While imbued, each time you hit a creature with an attack using this blade, it takes an additional 1d8 radiant damage. In addition each fiend within 10 feet of your target must succeed on a DC 15 Dexterity saving throw or take 1d8 radiant damage as crackling, radiant energy arcs out towards it.
  Demon Lure. As a bonus action while holding the blade, you can expend 1 charge to draw the attention of one creature you can see within 30 feet of you, forcing it to make a DC 15 Wisdom saving throw. A creature with the fiend type makes this saving throw with disadvantage. On a failure, the creature becomes fixated on you. For the next minute the creature’s speed is reduced to 0 and it is incapacitated. This effect ends if you attack any other creature, if you cast a spell, if the target of this property is affected by a spell cast by a creature friendly to you, or creature or if a creature friendly to you damages the target of this effect.
  Uncommon variant: Decrease the DCs to 13 and the damage of Radiant Wrath to 1d4.
  Very rare variant: Increase the DCs to 16 and the damage of Radiant Wrath to 1d12.
  Legendary variant: You can speak Celestial fluently and can expend a charge to cast the spell protection from evil and good, no concentration required, protecting the target from fiends only. Increase the DCs to 17 and the damage of Radiant Wrath to 2d8.