Bloodsong (5e Equipment)
From D&D Wiki
Weapon (longsword), Legendary (requires attunement by a creature of chaotic evil alignment)
Lore There is a legend of a Bard and his child who lived in a quiet mountain village, safe from any harm until legions of soldiers and mercenaries from the city nearby arrived to conquer the humble settlement under orders from the tyrant king of the metropolis. Unable to defend themselves, the villagers surrendered. However, the armies slaughtered the men and children, enslaving and raping the women. The lucky bard and his son escaped with about 20 people into the nearby woods - they were the only survivors...
Before long, the soldiers discovered the forest haven and utterly ravaged the villagers left, burning many and killing more and more. The innocent bard, still hidden, revealed himself in an attempt to make peace by playing a bittersweet tune and begging for them to stop. Laughing at the frail man, the soldiers made him watch the killing of all the children in the town, who liked him dearly and would often listen to his stories and music, before then burning him for being a 'Traitor'.
His dear son (still in hiding) saw every second of this brutal killing and ,with tears in his eyes and a heart dying with grief, made a solemn vow to avenge his father .He made a prayer to the gods of good fortune and justice. Alas, they ignored him, to busy to help a single, worthless child. Enraged with a hate and fury far greater than any other mortal has ever felt, the child sent a desperate call out to Orcus, the demon prince of Undeath. Hearing his call, the demon price gave him a blade so malicious and powerful it made the gods themselves tremble. It made him invulnerable and fuelled him with power. Rushing to his father (who was almost dead),he promised him to have revenge. His father nodded with his head before he succeeded to the eternal sleep which is death. Berserk and in a frenzy, the child threw himself at the soldiers, mangling and utterly destroying them as he laughed and bathed in their cries of pain and their begs of forgiveness. Within an hour, all the soldiers in the valley in which the once safe town lay were dead. But this was not enough.
The spirit of Orcus had infused him with anger and cruelty. He travelled to the city where they came from and exacted revenge on them as well, relishing in the death he caused. But this was not enough to quench his thirst for destruction. He engulfed everything on that continent with his flame of hatred, leaving no survivors but himself on the land. When he stopped, he was freed from the grasp of the sword and realised the catastrophe he had caused. With a cry of pain, and horror, and depression, he threw himself onto the blade, staining the metal crimson with his blood. From then on the blade was possessed with the spirit of the boy, ever hungry for death, and in memory of his father, the sword played a eerier, heart-breaking version of his father's favorite song whenever blood was spilt. The blade was called Bloodsong.)
Possessing a crimson blade, a ebony steel hilt and a pommel shaped like a miniscule skull, Bloodsong is a magic sentinel longsword embowed with necrotic energy that consumes peoples souls and feasts on their sorrows.
Traits. You can select a chosen creature to be your 'hated enemy'. You are resistant to damage dealt by non-magical weapons by them and you instantly win any saving throws they force you to make. You can only have one 'hated enemy' at a time and you can choose up to 3 of them in your life. You gain a +2 bonus to attack rolls and damage rolls with this magic weapon. It deals an extra 1d10 necrotic damage to 'hated enemies'.
While wielding you are immune to necrotic damage and the sword deals 2d8 necrotic damage to targets you hit. You may wield it for as long as you feel a strong hatred and need for revenge. Once you have sorted out the problem, you must make a successful Constitution saving throw (DC 20) or take 55 (10d10) damage. If you are killed this way, your soul is absorbed by the blade.