Agnamelek, The Twin Suns

In very, very ancient times, perhaps near the early beginnings of the multiverse, there used to be a comet wandering in the sky from time to time. People soon learned to hate it, because it always appeared before a huge calamity, such as a devastating earthquake or a century-long war. They called it Agnamelek, harbinger of doom. Due to the fact the comet displayed a bizarre shape, as it was made by two smaller comets constantly revolving one around the other, and also thanks to its exceptional brightness, so great that it illuminated nights like they were days, it was also dubbed it The Twin Suns. Agnamelek was visible not only from the material plane, but also from other planes. Denizens of the lower planes were especially interested in it, given its peculiarities. For centuries the most erudite demons and devils racked their brains to discover its origin and the source of its power. One day, a very powerful archdevil, certain that the comet hid a treasure beyond any comprehension, came up with the manner of bringing the comet to Baator. To accomplish this, he called the most powerful wizards of the Nine Hells and together they performed a spell which power had never been seen in the prior ten thousand years. Thanks to this effort, the comet crashed upon Avernus' surface, the first layer of Baator. The archdevil, whose name is lost through the maze of history, immediately reached the landing site and what he found surprised him above all expectations. Lying at the floor of the hundred-foot crater, there were two swords. The blades were shining with arrogance at the sun, giving to watchers the feeling of being in the presence of a tremendous power. The archdevil was going to take the swords, but an unexpected event prevented that. Despite the business being secret, some information became known to the citizens of the Abyss, which didn't want to lose such a marvelous opportunity. They attacked in mass and a huge clash begun. Soon more from either side joined the battle, and from then demons and devils are occupied in the conflict known as the Blood War. Since then, Agnamelek has been sought after demons and devils, and changes master every so often. Whosoever possesses it is pervaded by the will to fight, which is the reason why its holder never leaves the battlefields of the Blood War. When the planar boundaries were sealed and the travel disallowed, Agnamelek's master was Zariel, a very belligerent archdevil and skilled swordmaster. Then, two hundred years after the Cataclysm, when the barrier was broken, the Blood War started again. It is said that Zariel was later killed by a Balor after an incredible battle, and that the Balor became the new master of the twin suns. His name was Alzrius, and after such a battle, he was reformed and promoted to the status of Demon Lord. Since then, he is known throughout the multiverse as Alzrius, the Lord of Infernal Light.

Agnamelek are two +3 longswords. They deal an additional 2d8 hellfire damage with every hit (hellfire damage acts as fire damage except it ignores fire resistance and fire immunity is treated as resistance). When they are swung they burst out a tongue of flames, effectively giving them a reach of 60 ft. Unlike other weapons with reach, they can be used at any distance within the reach without penalties. In addition, every creature that brandishes Agnamelek automatically gains the following, without needing to meet the prerequisites:

Two-Weapon Proficiency. You can use two-weapon fighting even when the one-handed melee weapons you are wielding aren’t light (as if from the Dual Wielder feat). And you also gain the Two-Weapon Fighting fighting style (when you engage in two-weapon fighting, you can add your ability modifier to the damage of the second attack).

Elemental Adept (fire). You gain the Elemental Adept feat for fire only (spells you cast ignore resistance to fire damage, and when you roll damage for a spell you cast that deals fire damage, you can treat any 1 on a damage die as a 2).

Agnamelek's peculiarity is that they fuse with the soul of their bringer, so that only he or she can use them. Agnamelek's master can summon the two swords in his hands or make them disappear (as if drawing or stowing a weapon, as if from the Dual Wielder feat). While the swords are not summoned, they are hidden within the master's soul. In addition, while Agnamelek are summoned and wielded by the master, they produce the following effects:

Fiery Aura. The temperature raises to extreme heat in the area within 60 ft. from the master. Every creature in the area takes 1d6 hellfire damage per point of Charisma modifier the master possesses at the beginning of their round (up to a maximum of 4d6). Hellfire damage overcomes all resistances and treats immunity as resistance. Metallic objects in the area are subject to the effect of a permanent Heat Metal spell (sentient magic items are allowed a CON save with DC equal to 14 + the master's Charisma modifier to avoid the effect).

Sunburn. The area within 60 ft. from the master is permanently under the effect of a 9th-level Daylight spell. This effect automatically dispels any magical darkness, regardless of level of spell that created it. Creatures that directly look at the master must make a CON save with DC equal to 14 + the master's Charisma modifier or become permanently blind. A creature that succeeds on the saving throw is immune to the effect for the next 24 hours.

Death Star. The master gains immunity to fire and cold, a bonus to AC equal to half its Charisma modifier (rounded down) and limited immunity to the Magic Missile and any spell targeting only the master of 2nd level or lower.

Agnamelek's Attunement. Whoever kills the current master automatically becomes the new master, and automatically gains proficiency with Agnamelek, regardless of other weapon proficiencies. A soulless creature (such a golem) cannot be the master. If such a creature happens to kill Agnamelek's master, then the first creature with a soul that touches the Twin Suns becomes their new master. The new master instantly attunes to Agnamelek, and if the new master already has the maximum number of attunement slots allowed used, one random non-cursed, non-artifact attunement is immediately unattuned to make room for Agnamelek's attunement. This attunement cannot be broken by any means except by the new master's death.

Agnamelek's Flaw. While attuned to Agnamelek, the master gains the following flaws:
"Fighting is the only reasonable resolution to conflict, and I never back down from a fight."
"I will do anything to keep possession of Agnamelek."

Proficiency with a Longsword allows you to add your proficiency bonus to the attack roll for any attack you make with it.

Notes: Bonus: Magic, Damage, Buff, Combat, Cursed, Versatile, Sap