Wraith and Wrath ∆
Weapon (dagger and shortsword), very rare (requires attunement)

Wraith and Wrath come in a pair, each crafted from dwarven dark iron with hilts made from the bone of a black dragon. Wraith, the dagger, is slightly curved with several sapphires inlaid along the blade. Wrath, the shortsword, is a thin, razor sharp blade with several matching sapphires inlaid along the blade.

If Wraith and Wrath are ever more then 120 feet apart, the dagger magically teleports to the side of the shortsword.

∆ Wraith is a +2 magic dagger with the following properties:

When thrown, the dagger ignores half-cover and three-quarters cover.

When thrown, the dagger can phase into the Ethereal Plane, and can pass through full cover to strike its target, as long as that cover does not extend into the Ethereal Plane. When making an attack in this manner, you have disadvantage on the attack roll, and the target receives a +5 bonus to AC, unless you are able to see the target through the cover.

∆ Wrath is a +2 magic shortsword with the following properties:

While wielding the shortsword in one hand, you can use a bonus action to cause Wraith to magically teleport to your free hand. If you don't have a free hand, Wraith returns to its sheath.

Once per dawn, while wielding Wrath, you can use your action to cause a bolt of lightning to arc from Wrath to Wraith in a 5 foot wide line. Each creature within the line must succeed a DC 14 Dexterity saving throw or take 26 (4d12) lightning damage. On a successful save, the creature takes half damage. A creature in contact with the Wraith automatically fails the saving throw. This bolt of lightning deals double damage to structures and objects. Full cover not destroyed by this effect interrupts the arc.

Wrath deals an additional 1d6 lightning damage on a hit.