This pair of ancient longswords contain the souls of two beings, an angel and a devil, both bound by an archmage to live forever as paired blades, never being able to harm one another. These weapons count as one for the purposes of attunement. 

You have a +3 to attack and damage rolls made using these magic longswords, and they both have the finesse property and can be used for Two-Weapon Fighting despite not having the light property.  

Extraplanar Health. While attuned, you have resistance to radiant and necrotic damage. 

Growing Fury. On a successful attack with Raum, you deal an additional 1d8 necrotic damage and your AC is temporarily increased by 2 until the start of your next turn, as Abbadon seeks to impress you with its protection magic. On a successful attack with Abbadon, you deal an additional 1d8 radiant damage and Raum's next attack does an additional +5 damage, as it seeks to destroy your enemies better than Abbadon.

 Wormwood. As a bonus action, you can combine the swords into an accursed polearm called Wormwood. Wormwood has a +3 to attack and damage rolls, deals an additional 2d8 radiant and 2d8 necrotic on a hit, has the finesse property, and lacks the heavy property.

Curse of Mixed Divinity. As a bonus action while holding the spear, you may launch it up into the air and bring it down on a point within 60 feet, sending it halfway into the ground underneath, where it then explodes energy outwards in an apocalyptic blast of cursed energy, forcing every creature within 10 feet to make a DC 17 Dexterity saving throw or take 5d8 radiant and 5d8 necrotic damage, or half on a success. After the explosion, the ground in the radius is cursed for 1d4 rounds, forcing every creature that starts its turn there or enters it for the first time on a turn to make a DC 17 Constitution saving throw or take 2d8 radiant damage and 2d8 necrotic damage, or half on a success. This bonus action can only be used once, and refreshes at dawn. 

Sentience. Abbadon and Raum are sentient items. Abbadon is lawful neutral, with an Intelligence of 12, Wisdom of 20, and Charisma of 18. It has hearing and truesight out to a range of 120 feet. Raum is neutral evil, with an Intelligence of 20, Wisdom of 13, and Charisma of 17. It has hearing and truesight out to a range of 120 feet. They both communicate via telepathy with any creature touching them. Both swords bicker between eachother regardless of situation, only ceasing when merged into Wormwood. They offer conflicting advice occasionally, acting as an angel and devil on each shoulder. 

Notes: Resistance: Radiant, Resistance: Necrotic