Guild Wars 2

Each legendary weapon to have a Legendary Quest in order to obtain it. The quest is started by talking to certain NPC specific to that weapon. Below is my example for Kudzu-Legendary Longbow. Only changes made to obtaining the weapon is omission of precursor, all other ingredients remain the same.

NPC- The Avatar of the Pale Tree
Story- Kudzu was a legendary bow bequeathed by the Pale tree to the first ranger valiant, however when that valiant fell in battle,the bow withered away and only a leaf of the kudzu remained that was managed to be brought pack to the pale tree. If you truly wish to restore the Kudzu, then prove your determination to undertake this quest to the Pale tree. Present a Gift Of Kudzu to the Pale tree to show your resolve to restore Kudzu.

First quest- The avatar explains the method of obtaining the Gift of Kudzu,after the player has acquired it, the gift of kudzu is presented to the Pale tree. The pale tree acknowledges your determination and bequeath to you the leaf of kudzu ( Quest item-Not weapon )

Second quest- The avatar explains that the leaf of kudzu is a powerless relic now and before it can be restored, the Kudzu will decide if the player is truly the one meant to restore it. To achieve this the player has to obtain Mystic Clovers to present to Kudzu.

Third quest- The Kudzu has accepted the player and the Avatar explains that it is now time to restore the Might and Magic of the Kudzu. The Player will now need to obtain
the Gift Of Magic,the Gift of Might and Globs of ectoplasm to bind it to the weapon.

Final Quest – The Kudzu has been restored but before it can be given to the player, the Avatar of the Tree gives you a final task. Prove to the pale tree that you have mastery over the realm so that you can be deemed worthy to wield the Kudzu.
The player will need to present a gift of battle proving his ability in combat,a gift of exploration proving his experience in adventure,obsidian shards to prove his quantified Karma and deeds in this realm and a bloodstone shard to prove his depth of skills in his profession. The Kudzu is only then bequethed to the player thus ending the Legendary Quest.