Hit points lost to this weapon's damage can be regained only through a short or long rest, rather than by regeneration, magic, or any other means.
Once per turn, when you hit a creature with an attack using this magic weapon, you can wound the target. At the start of each of the wounded creature's turns, it takes 1d4 necrotic damage for each time you've wounded it, and it can then make a DC 15 Constitution saving throw, ending the effect of all such wounds on itself on a success. Alternatively, the wounded creature, or a creature within 5 feet of it, can use an action to make a DC 15 Wisdom (Medicine) check, ending the effect of such wounds on it on a success.
Proficiency with a Scimitar allows you to add your proficiency bonus to the attack roll for any attack you make with it.
This weapon has the following mastery property. To use this property, you must have a feature that lets you use it.
Nick. When you make the extra attack of the Light property, you can make it as part of the Attack action instead of as a Bonus Action. You can make this extra attack only once per turn.
Notes: Damage: Necrotic, Damage, Combat, Finesse, Light, Nick
Huh... I was just comparing this "Scimitar of Wounding" to the "Scimitar of Speed" ... https://www.dndbeyond.com/magic-items/4752-scimitar-of-speed
Both in the basic rules, so there was no gradual powercreep there. The other scimitar is "VERY RARE" instead of "just" Rare.
But i feel like this scimitar is a bit better? Sure, no bonus action option, but the only martial in my group already has a good use for their bonus action... and 1d4 necrotic damage for each hit, stacking with each other? Even if you roll below average and only get a 2 on each d4, that's still on par with the much rarer speedy scimitar. Counters healing and regeneration too, so this counters Trolls and Vampires etc. quite good.... If my Party gets to choose between buying this scimitar, or the much rarer scimitar with a high discount to be the same price as this wounding scimitiar...they might still go for the lesser rarity one. Interesting.
But yeah, the bonus action extra attack thing is quite good, if there is no other use for bonus action.