It would appear that Mew had a relationship with Celebi at one time, before he got his job on the show.
Mew is obnoxious in every way. He loves drama, and loves causing chaos and craziness all around. This often gets him on the bad side of most competitors throughout the show, though he is shown to get along with a good few (Piloswine is a great example of this). Just as Mewtwo has a hatred and rivalry towards Banette, Mew has a hatred towards Hitmonlee, and a humorous dislike of Bronzong.
According to many, Mew was not always a jerk, but was once considerate and kind. It is currently unknown what changed him to who he is today.
- In the Krazy Kyogre's Kalamaty Kwiz game, it is revealed that Mew is carnation pink.