Guild Wars 2 DevilDragons

With great thanks to the Guild Wars 2 community, we now have the formula for crafting legendary weapons. Below is the Master Recipe for legendary weapons and all the sub-components required to craft them:

Base Exotic Weapon
Base Gift
Gift of Mastery: Bloodstone Shard + 250x Obsidian Shard + Gift of Exploration + Gift of Battle
Gift of Fortune: 77x Mystic Clover + 250x Glob of Ectoplasm + Gift of Magic + Gift of Might

Base Exotic Weapon
They can be obtained by throwing 4 rare/exotic weapons above level 76 (research ongoing) of the type you want to obtain into the Mystic Forge (4x Greatsword for Dusk or Dawn) and getting lucky. Or you might be able to obtain them as loot from events or enemies while being out in the world.

Staff - The Legend of Rage - Used for: Bifrost
Sword - Zap of Rage - Used for: Bolt
Torch - Dragons Claw of Rage/Rodgort's Claw of Rage - Used for: Dragons Maw/Rodgort
Shortbow - The Lover of Rage - Used for: The Dreamer
Shield - The Seeker of Rage - Used for: Flameseeker Prophecies
Speargun - Rage of Rage - Used for: Frenzy
Axe - Tooth of Frostfang of Rage - Used for: Frostfang
Warhorn - Howl of Rage - Used for: Howler
Dagger - Spark of Rage - Used for: Incinerator
Hammer - The Colossus of Rage - Used for: Juggernaut
Longbow - Leaf of Kudzu of Rage - Used for: Kudzu
Trident - Venom of Rage - Used for: Kraitkin
Spear - Maw of Rage - Used for: Maw of the Deep
Scepter - Storm of Rage - Used for: Meteorlogicus
Focus - The Bard of Rage - Used for: Ministrel
Mace - The Energizer of Rage - Used for: Moot
Rifle - The Hunter of Rage - Used for: The Predator
Pistol - Chaos Gun of Rage - Used for: Quip
Greatsword - Dawn of Rage - Used for: Sunrise
Greatsword - Dusk of Rage - Used for: Twilight

Base Gift
You need a specific Superior Sigil depending on what you want to craft, but they are most likely themed. Also the Mystic Forge won't accept any other sigils than the one that works with the specific components you threw into it (as far as we know).

Base Gift Recipe: Crafting Gift A + Crafting Gift B + 100x Icy Runestones + Superior Sigil of X

Base Gift Sub-Gifts

Staff - Bifrost = Gift of Color & Gift of Energy
Sword - Bolt = Gift of Metal & Gift of Lightning
Torch - Dragons Maw/Rodgort = Gift of Wood & [Not found in-game]
Shortbow - The Dreamer = Gift of Wood & Unicorn Statue
Shield - Flameseeker Prophecies = Gift of Metal & Gift of History
Speargun - Frenzy = Gift of Wood & Gift of Water
Axe - Frostfang = Gift of Metal & Gift of Ice
Warhorn - Howler = Gift of Wood & Wolf Statue
Dagger - Incinerator = Gift of Metal & Vial of Liquid Flame
Hammer - Juggernaut = Gift of Metal & Vial of Qucksilver
Longbow - Kudzu = Gift of Wood & Gift of Nature
Trident - Kraitkin = Gift of Energy & Eel Statue
Spear - Maw of the Deep = Gift of Metal & Shark Statue
Scepter - Meteorlogicus = Gift of Energy & Gift of Weather
Focus - Ministrel = Gift of Energy & Gift of Music
Mace - Moot = Gift of Metal & Gift of Entertainment
Rifle - The Predator = Gift of Wood & Gift of Stealth
Pistol - Quip = Gift of Wood & Gift of Entertainment
Greatsword - Sunrise = Gift of Metal & Gift of Light
Greatsword - Twilight = Gift of Metal & Gift of Darkness

Base Gift Sub-Components

Lodestones used for crafting weapon-specific Gifts drop from the following Dungeons as far as we know:
- Twilight Arbor - Onyx Lodestone
- Citadel of Flame - Molten Lodestone
- Honor of the Waves - Glacial Lodestone
- Crucible of Eternity - Charged Lodestone
- Arah - Corrupted Lodestone
- Unknown Locations
  - Destroyer Lodestone - Drops off Destroyers in Mount Maelstrom
  - Crystal Lodestone

You can also make Lodestones in the Mystic Forge if you have the core equivalent (one tier below lodestones): 2x Core Type + 1x Crystal + 1x Bottle of Elonian Wine + 1x Pile of Crystalline Dust

Dungeon Gifts: obtained at the vendors in LA that also sell dungeon armor. Each costs 500 Tokens from their respective dungeons.
Icy Runestones are obtained after defeating the Claw of Jormag in Frostgorge Sound for 1 gold each.

Sigils

Staff - Bifrost = Superior Sigil of Nullification
Sword - Bolt = Superior Sigil of Air
Torch - Dragons Maw/Rodgort = Superior Sigil of Fire
Shortbow - The Dreamer = Superior Sigil of Purity
Shield - Flameseeker Prophecies = Superior Sigil of Battle
Speargun - Frenzy = Superior Sigil of Rage
Axe - Frostfang = Superior Sigil of Ice
Warhorn - Howler = Superior Sigil of Accuracy
Dagger - Incinerator = Superior Sigil of Fire
Hammer - Juggernaut = Superior Sigil of Sanctuary
Longbow - Kudzu = Superior Sigil of Conjuration
Trident - Kraitkin = Superior Sigil of Venom
Spear - Maw of the Deep = Superior Sigil of Agony
Scepter - Meteorlogicus = Superior Sigil of Air
Focus - Ministrel = Superior Sigil of Energy
Mace - Moot = Superior Sigil of Energy
Rifle - The Predator = Superior Sigil of Force
Pistol - Quip = Superior Sigil of Stamnia
Greatsword - Sunrise = Superior Sigil of Strength
Greatsword - Twilight = Superior Sigil of Leeching

Gift of Mastery and Gift of Fortune Sub-Components

Obsidian Shard: obtained from Tactician Deathstrider at the Temple of Balthazar in Straits of Devastation for 2100 karma each.
Gift of Exploration (x2): obtained by reaching 100% World Completion
Gift of Battle: obtained from any weaponsmith in the WvW area for 500 Badges of Honor
Mystic Clover: rarely obtained in the Mystic Forge with this recipe: 10 Obsidian Shards + 10 Mystic Coins + 10 Glob of Ectoplasm + 10 Crystals
Gift of Magic: 250x Vicious Fang + 250x Armored Scale + 250x Vicious Claw+ 250x Ancient Bone
Gift of Might:250x Vial of Powerful Blood + 250x Powerful Venom Sac + 250x Elaborate Totem + 250x Pile of Crystalline Dust
Mystic Coin: rewards for daily/monthly achievements (also available on the Trading Post)
Glob of Ectoplasm: obtained from salvaging 70+ rare/exotic items with at least a Master's Salvage Kit
Crystal: obtained from Miyani for 3 skill points per 5 crystals

Image Gallery
Unfortunately we were not able to get screenshots of all the legendaries, but here are the ones we did manage to find:

Maw of the Deep

Spoiler