Whats with all the legendarys?

[Rayquazaking]

Ok soooo theres alot of legendarys out there, but what do they all do?!

i know hoho is some kind of peace maker and the legendary dogs are his spys but what about lugia and the legendary birds?

then theres latios and latias, what r they for? groudon is the god pokemon of ground or w/e and krygore (spelling bad) is the god of water pokemon urgh, i duno Rayquaza is just some flying superpowerd pokemon who broke up a fight between groudon and kygore, why is he legendary?

som1 fill me in

AND the regi's whats the story with them? and unknown?! AHH im confused. Tell me if i have missed some legendarys.

[the master]

The regis are guardians.
Mew's job is to be legendary.
Mewtwo is the god of slaughter.
And the other ones i don't know.

[Rayquazaking]

what are the regis guardians of? the caves where you find them?

[dragon_berry]

This isn't at the game but if you watch the movie of 'Lucario and the mystery of mew' the regi's job would be revealed so buy 'em in the nearest store (Guess what I'm a good tv star)