This Longsword was once in the possession of the first Great Elvin king, a ranger who united all of the Elves into one group. Upon his death, the Blade was seen as a holy item for many years, until the elves fragmented once again. It somehow wound up in the Lair of a Silver Dragon. Part of his soul still dwells within the Sword, giving it a peaceful personality, it wants to be reunited with the rest of the Elvin King's equipment, especially its twin.

This Longsword resembles an ancient tree, the hilt connecting to the blade, like roots to a tree, the blade like the trunk of the tree. This longsword is the larger of the two blades. When It's one charge is being used, ethereal branches that can be seen on the material plane grow from it.

This longsword is a sentient weapon that can speak Common and Elvish, both telepathically, and verbally. It has darkvison to 30ft.

The longsword is light enough that you can use it's versatile ability while wielding it in one hand. I.E. Use the 1d10 instead of the 1d8

Between the longsword and shortsword, his knowledge of foes and languages is split, while this blade knows every weakness of every creature, the shorter blade knows all languages, and shares them with it's master when attuned.

While attuned to this blade you gain the effects of the Ranger Class ability Favored Enemy for ALL creatures

You have advantage on Survival checks to track your favored enemies, as well as on INT checks to recall information about them. You also learn one language of your choice that is spoken by your favored enemies, if they speak one at all. PHB91

When Attuned to BOTH blades you also gain the effects of Foe Slayer

Once on each of your turns, you can add your wisdom modifier to the attack roll or the damage roll of an attack you make against one of your favored enemies. You can choose to use this feature after the roll but before knowing its effects. PHB92

You gain a +3 bonus to attack and damage rolls made with this magic weapon. In addition, the weapon ignores resistance to slashing damage.

The Longsword's blade is extremely sharp, dealing 3d10 instead of 1d10.

Once per round, on a hit, a target must make a DC18 con saving through or take 5d8 poison damage, or half as much on a successful save.

When you attack a creature that has at least one head with this weapon and roll a 20 on the attack roll, you cut off one of the creature's heads. The creature dies if it can't survive without the lost head. A creature is immune to this effect if it is immune to slashing damage, doesn't have or need a head, has legendary actions, or the GM decides that the creature is too big for its head to be cut off with this weapon. Such a creature instead takes an extra 8d8 slashing damage from the hit.

Other Elvin King's Equipment

Elvin King's Bow

Elvin King's Quiver

Great Elvin King's Blade; Ragnarok

Great Elvin King's Cloak

 

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: Poison, Damage: Slashing, Weapon Property: Finesse, Favored Enemy: Werewolves, Favored Enemy: Wererats, Favored Enemy: Wereboars, Favored Enemy: Werebears, Favored Enemy: Undead, Favored Enemy: Sahuagin, Favored Enemy: Plants, Favored Enemy: Orcs, Favored Enemy: Oozes, Favored Enemy: Monstrosities, Favored Enemy: Merfolk, Favored Enemy: Lizardfolk, Favored Enemy: Kobolds, Favored Enemy: Humans, Favored Enemy: Halflings, Favored Enemy: Grimlock, Favored Enemy: Goblinoids, Favored Enemy: Gnomes, Favored Enemy: Gnolls, Favored Enemy: Giants, Favored Enemy: Fiends, Favored Enemy: Fey, Favored Enemy: Elves, Favored Enemy: Elementals, Favored Enemy: Dwarves, Favored Enemy: Dragons, Favored Enemy: Dragonborn, Favored Enemy: Constructs, Favored Enemy: Celestials, Favored Enemy: Beasts, Favored Enemy: Aberrations, Elf or Ranger, Damage, Combat, Versatile, Sap