Kelemvor's Shroud

As a bonus action you can activate this ring to become invisible for 1d6 minutes OR to imbue your weapon with the power of Kelemvor, casuing your next attack which hits to deal 2d10 necrotic damage and heal you for half the total damage, rounded down. This can only be used once per day.
You have advantage on all attacks against Undead and on death saving throws. On attacks against Undead add one additional damage die to the roll.