Let's see... Pretty hard this one.
I think it's Latios, as he is Latias older brother (first of his generation), but his father was a Latios too (not first of his kind), Also, Latios is a flying/psychic dual type and is a roaming pokémon.
I have two:
"Even though I'm supposed to be one of the worst things in existence, everybody loves me. My own existence defy the laws of physics, and my own presence freezes times and makes space collapse. And even if someone dares to catch me, I always escape. I'm the Missing Number. Who am I?"
"Me and my brothers,
each live alone,
in a place
near a Mystery Zone.
We each ventured
in our own Mystery Zone,
and to our great surprise
each of us found a small pond."
Edit: Nobody is answering :-\ ? Why won't anybody answer? My riddles are so cool...
Also, to those who don't know what Mystery Zones is, is a place in the Generation IV games that can only be acessed by the walk throught walls cheats, which exists everywhere in the Generation IV games and is basically just a lange black zone where nothing resides. But there are three places whose respective Mystery Zones have small pond on them.