The Fairy Legendary Pokémon are small, imp/fairy-like Legendary Pokémon who have one or more types (one always being Psychic, except in the case of Manaphy, who is purely a Water-type). To date, every Generation of Pokémon games features only one Fairy Legendary, and the Fairy Legendary is only obtainable through a special event. There are currently five Fairy Legendary Pokémon, one from each generation of Pokémon.
Although Manaphy is a Fairy Pokémon, it has some features that are similar to a regular Pokémon.
It is purely Water-type. (Every other is part Psychic-type, Mew being fully Psychic.)
It can breed with Ditto to get a Phione egg (Manaphy is the onbly Legendary to actually breed.)
If Mew is accounted as earth-like, then the five 'Fairy Legendary Pokémon' would fit with the Chinese elements, fire, water, earth, wood and metal.
All of these Pokemon have 100 base stats for all six stats.
In each regional Pokédex (minus the platinum extension Pokédex) Mew, Celebi, Jirachi and Manaphy all appear either last, or in Jirachi's case, second-to-last, though, Victini appears at the start of its Regional Pokédex (Unova).
Shaymin could possibly be another Fairy Legend Due to the striking similarities to the others. This could just be a coincidence though.
Added by Crimsonnavy