Cursed Sword Feedback

I've been working on a new end-game kinda of weapon for Hexen, specifically for Baratus. I'm trying to go for a theme of it being a very powerful weapon but it having a slight negative effect on the player in exchange for more power, while still feeling semi balanced.

Currently the weapon is, in my opinion, slightly more powerful that his Quietus. Outputting near the same amount of damage with the alt fire, three dark energy slashes that rip through enemies, but also including a decently damaging primary fire, which is a melee attack that cuts through the fabric of time and space to open up a small gash into a dark void that pulls enemies in while also dealing another hit. However, when the player is using this weapon their speed is reduced slightly while idle, and reduced even more if they decide to hold their swing to get a better aim, and it takes a little longer to swing the large and heavy sword. This is the negative effect the weapon gives the player in exchange for more power, hence the name, Cursed Sword.

The mechanics are all done and functions as I want it too for now. The only thing that is missing are some sounds, and of course much needed feedback. I have been wondering if this weapon in its current state really is balanced enough and I would love some feedback regarding this. I'd like to keep the theme of power exchanged for a slight negative effect though because I think it's a neat idea and hasn't really been done before. And of course I am open to any other feedback outside of balancing.

...also, does anyone have any decent sounds to go along with this weapon? Specifically some kind of dark magic feel for the projectiles and the void that appears with the primary fire.

The Cursed Sword