Articuno
Gender: ♀
Birth Name: (UNKNOWN)
Personality: Curious but shy, calm-minded, protective of her family…
Favorite color(s): Cyan, Yellow, White
Time of Birth: 5000 years ago (approx.)
Time of Death: less than 5000 years ago (approx.)
Time of Rebirth: less than 5000 years ago (approx.)
Form before Rebirth: Human
Hair Color: Icy Blue
Favorite Animal(s): Poison-Arrow Frog, Dromeosaurids, & Birds
Parentage: Lugia (biological father), unknown human (biological mother, deceased), Ho-oh (surrogate mother/biological aunt), Arceus (biological grandfather)
Cause of Death: Murder by Demon

Zapdos
Gender: ♂
Birth Name: (UNKNOWN)
Personality: Headstrong, stubborn, hyper, energetic, protective-borderline possessive…
Favorite color(s): Yellow, Navy Blue, Black, Grey…
Time of Birth: 5000 years ago (approx.)
Time of Death: less than 5000 years ago (approx.)
Time of Rebirth: less than 5000 years ago (approx.)
Form before Rebirth: Human
Hair Color: Black with Bronze accents
Favorite Animal(s): Theropods (Two-legged Dinosaurs)
Parentage: Lugia (biological father), unknown human (biological mother, deceased), Ho-oh (surrogate mother/biological aunt), Arceus (biological grandfather)
Cause of Death: Murder by Demon

Moltres
Gender: ♀
Birth Name: (UNKNOWN)
Personality: Mellow yet stern, hopeful, sympathetic, mature…
Favorite color(s): (UNKNOWN)
Time of Birth: 5000 years ago (approx.)
Time of Death: less than 5000 years ago (approx.)
Time of Rebirth: less than 5000 years ago (approx.)
Form before Rebirth: Human
Hair Color: Crimson Red (?)
Favorite Animal(s): Bears, Ceratopsians, Rabbits, Birds, Stegosaurs
Parentage: Lugia (biological father), unknown human (biological mother, deceased), Ho-oh (surrogate mother/biological aunt), Arceus (biological grandfather)
Cause of Death: Murder by Demon

Biography:
Articuno, Zapdos, and Moltres were once the human offspring of a beautiful, young woman and of the Guardian of the Seas, Lugia. All three were born and named during a time that many identify as the 'Biblical Age' on Earth. They lived happily with their mother on Earth for seven years, until an unknown demon murdered their mother, leaving them under the loving care of their father. Until their mother's murder, the triplets were visited by their father in disguise, and were unaware of his true nature, having been told by their mother that their father was an angel.

Though they didn't believe it at first, the children came to accept and love their father as they had their mother, but they could feel their father's grief over the loss of their mother, and his anger to kill their mother's murderer. The three children could only spend so much time with their father as mortal offspring, so much of their lives were spent on Earth, believed by other humans as orphans. Their father is often busy, but tries to visit his triplet children as much as he could, which is roughly in a two year interval.
By the triplet's 16th birthday, they came to be respected by many of the other humans as exceptional farmers, and due to their parentage, the desire of men and women. The three were not adults yet, but the daughters had already become the most beautiful women, and the son, the most handsome man, the humans had ever seen. Many men sought either of Lugia's daughters hand in marriage, but were chased off by either Lugia (when he's around) or his son. By the time all three are 18 years old, a mysterious man had convinced the triplets to follow him to this unknown location where they were greet by their mother, somehow alive.

Initially confused at the fact their mother was alive, and hadn't aged a day, they couldn't care less and embraced their mother. But then, the children noticed her skin was cold, and she smelled like a body that had been dead for years, the man was revealed to be the demon that had murdered their mother, and two more demons erupted from their mother's corpse. They cried out for their father and tried to escape from the demons, who wish to kill them in cold blood. Lugia's rage was building at the fact his children were in danger, starting the events that would lead to what many ancient people would come to call, The Great Flood…
Eventually, the triplets head to where their father would know they would be, but they saw what looked like a dragon made of smoke fighting their father. The three children were too focused to realize their pursuers had caught up to them, then using three humans that had turned to wickedness, killed them all, much to their father's horror. Enraged, Lugia killed the human murderers, while the demons escaped, pleased to have accomplished their goal; have Lugia instill fear into all of mankind.

The spirits of the children could only watch in horror as their father, in his rage, attack and destroy thousands of humans, many of their human friends among the unfortunate. Ho-oh revived the three in new forms like those of birds, with much of their memories of their past lives lost. They were reintroduced to Lugia, the reborn children were unaware that he's their father, but were adopted by him, oblivious of their past lives, and eventually became the guardians of nature and heralds of the seasons…

Here's the first of several…uh…things, explaining my headcanon for the Legendary Pokémon, I'd very much to hear your thoughts, your theories of when this exactly takes place, your questions, etc.
If you want more, don't worry, I'll get to more made, in order, but let me know if you want to see one or a few before hand. I await your comments…

Nice mixture of real world mythos with Pokemon world

4785382 Thanks...My headcanon not only ties the real world, but many other fictional universes as well, and I'm using it for my own Pokemon fanfiction: Pokemon - The Equestrian Chronicles...
Is there a Legendary Pokemon you want to see my headcanon for? Because the next I'm doing is Mew, unless you really want to see one before the other...
Might add pictures of what they look like in another form (predominantly human), because they all have the potential to assume the shape of any sentient race, down to the anatomy...

4785484 the doggie trio?

4785780 I'm working on the Legendary Beasts, but, I must ask;
What do you think of my headcanon of the Legendary Birds? Are there any questions you have about them?

Please respond...

4787942
*shurgs*
Pretty cool!

4788072 I did one of the Legendary Beasts...
I'd like to hear your feedback on them...

4785350 Quite interesting. I think you've got their personalities down to a T.

4785484
The Creation Trio is something that sounds really cool. Or Kyurem.

4823819 k :D

4824148 Thanks...

4824251 Oh do I have one of those four, kind sir/mam...But, before I do, I was recommended by the founder to follow the National PokéDex order, so you will have to wait a while for the Creation Trio, and even longer for Kyurem...

4825405
No problem. If it is anything like what you did for the Birds/Beasts, then I can wait.

(Also, I'm a sir.)