Rebalancing Blood Fury Tattoo and requesting feedback

So here's a bit of context: We played the "Don't Say Vecna" one-shot recently as a post-level 20 party of two (we were down a couple of players so we stepped away from our campaign for a session). After whooping Vecna's ass back to the void, my Abjurer Wizard teammate looted the nice Book of Vile Darkness. And as a Path of the Giant Barbarian, I was like "can I get something cool too?", so the DM said "you can pick a Legendary item that is evil-themed", so I picked the Blood Fury Tattoo, and the DM approved.

Fast-forward the next day, I take a deeper look at the Book that the Wizard looted and realized just how much of a poisoned gift it was, then I ran the maths on the DPR boost given by the tattoo and realized it was insane and now I was the one who got the bigger reward. So I figured, if my teammate got a cursed reward, let's curse mine too. And so I came up with this:
https://www.dndbeyond.com/magic-items/11975311-vecnas-blood-fury-tattoo

Cursed. Vecna's Blood Fury Tattoo is cursed, a fact that is revealed only when the Identify spell is cast on the needle or you attune to it. Attuning to the tattoo curses you until you are targeted by a Remove Curse spell or similar magic. Removing the curse ends your attunement. While cursed, you are unwilling to end your attunement to the tattoo or part with the needle.

While cursed, you experience the following effects:

• No Prisoners. Whenever you attempt to inflict non-lethal damage, you must succeed a WIS saving throw or do lethal damage instead.
• Bloody Overkill. Whenever you hit a creature with an attack roll and kill it, you must succeed a WIS saving throw or use your next attack to target the creature's corpse and tear it apart. You don't need to make a save if you cannot attack anymore on the current turn or if the creature left no corpse (like a Ghost). 
• Furious Retaliation. The first time in a round you take damage from a creature, roll a WIS saving throw. On a fail, your next attack or action during this round must be used to damage that creature if you can see it.

Escalating DC. The DC of the aforementioned WIS saves starts at 0 and increases by 5 every time you consume a charge of Vecna's Blood Fury Tattoo. It resets to 0 when combat ends or if you are Incapacitated.

The No Prisoners is mostly flavor and roleplay. It just doesn't make sense to me that an item that makes it difficult for you to control yourself would allow you to refrain from killing a target.
Bloody Overkill is where the big tax happens. The more you use the tattoo, the more you risk wasting attacks on your turn, which is a big loss of damage for a Barbarian. Furious Retaliation also might force you to target a dying or weak target instead of focusing on the BBEG, and waste even more attacks. It can also prevent you from using the tattoo's reaction on the current round if you get attacked from too far away. Escalating DC is based on the same concept as Relentless Rage. The more you use the tattoo's power, the more you lose control, until you're forced take a turn to cool down and regain your composure.

I did my best to do something that wasn't too verbose and required to write a novel to explain, that didn't clutter combat with too many rolls (this iteration of the curse caps at 2 saves per round, unless you really want to knock someone out), that didn't completely handicap the player or put them on autopilot, that wasn't too bad that it would knock it out of Legendary category, and that could make for funny roleplay moments.

What do you think?

The Book of Vile Darkness is essentially unusable by any character that doesn't want to become a villain, it's not really a reward it is a plot item. Most adventuring parties should simply seek to find a way to destroy the Book of Vile Darkness before it destroys them or escapes to find a new evil master (or another evil being seeks them out to claim it). So if you want your reward to be equivalent, it should have a similar restriction:

The Blood Fury Tattoo will only regain charges as long as you strive to work evil in the world. If you fail to perform at least one evil act since the last dawn, or if you willingly perform a good act during that time, the tattoo does not regain any charges. If you die while the tattoo is on your skin, an entity of great evil claims your soul. You can’t be restored to life by any means while your soul remains imprisoned.