Father de Watteau is not seen in the episodes very much. He travels without letting the other Vatican and AX members know where he went or when he will be back.
He has a certain hate for vampires, and can go on killing sprees to kill every vampire he sees.
Just like Tres, Hugue isn't very talkative. The scars on his body make it clear that he has been through a lot of pain.
In other words, he's too much of a badass to be caught hanging aroung a moralfag like Abel.