One (or two?) magic swords.

Yay there.
Need help and ideas for one, maybe two magic items.
Ok, let me drop some backstory.

One of the PCs in my ongoing Burning Midgard game, Eldric the elven Swordsinger, got his hands on the fabled sword Hrunding

Eldric took the sword back to its maker, Bròkkr the Dwarf, and convinced him to reforge it to make it more wieldable and serviceable.
Bròkkr accepted, because the sword was a work of you youth, and he was far from as expert an artificer as he was now. So he wasn’t able to use the White Metal Artifice quite effectively, and the sword was flawed. He merely sculpted the sword from the meteoric metal, not being able to melt it and forge the blade in a more fashionable manner.

Obviously Bròkkr will not let the Elf take back the sword without paying a high price, and this is going to be the main topic of the next few sessions.
Besides, I was wondering how the Dwarf could have reforged the sword. Being the meteoric metal of which was forged the original blade was plenty enough to make not one, but even two or more weapons, I was thinking of Brokkr having forged two twin blades, with similar yet different properties.
Then, maybe the nemesis of Eldric, Alfdar the Dark Elf, could have scouted Bròkkr cave, murdered the dwarf and taken one of the swords for himself; the other could’ve been hidden on a desperate last effort by the dying Dwarf.

Now: I want both the swords to be very powerful yet have a serious drawback.
The Dwarf forged them having in mind no one could ever wield them without being accursed or doomed to some dark fate; this is after all the stuff of many legends, from the sword Tyrfing of Norse myths to Tolkien’s Mormegil.

Following there is the basic writeup of the sword(s) stats, loosely based on Kublai’s Vorpal Sword.

Stats: +4 Power, Add 2, VA2, WS2, Longer, 2-handed, may Great Strike


Dashing Blade
Although larger than most, the sword is crafted from meteoric alloy, allowing the blade to be thinner and lighter yet more durable and sharp than any other. Add +1D Balanced to Sword Skill.

Legends Slayer
Ona successful attack, should the bonus die from the Dashing Blade trait result in a 6, the attack does Grey Shade damage.

If at any time no dice from the Sword pool come up with a success (e.g. all failed dice), the sword’s power backfires on his wielder.
He automatically suffers a Mark strike to a random location. Armor still apply.

If the bonus die from the Dashing Blade trait ever comes up in a 1, then the sword delivers a Mark strike to an adjacent ally of the wielder. If there’s no adjacent target to be hit, then apply the results as per the Fumbling trait.

Now some more powers to spice up the “twin swords” thing.
The two blades are made so that they attract each other in some way. Maybe the White Metal Artifice split the very substance of the meteoric metal in two alloys, magnetically opposite. The wielder of each sword coul at any time use it as a compass to reveal without error the direction (not distance) of the other sword. When dueling against each other, the two swords attract so much that the Balanced die is lost, but any Block action has +2D.

Not sure with the last bits, and needing general input on the other powers of the swords.
Any help appreciated!