In Prehistoric times, it was thought that mental illness was caused by magical beings playing tricks with the mind...
Mischievous to a fault, Trephan possesses what might be called a malicious sense of humour, and is often faintly sexual in his thought process which is referenced in his speech in the form of innuendo more often than not. To a woman, specifically a woman that he has some form of interest in, he appears to be a gentleman, and is generally rather polite when he wants something.
As a general rule, men and older people of both genders bear the brunt of his bad behaviour, which tends to be more mocking than actively aggressive. He has not been known to raise a hand to a mortal with the intent to wound or kill, though occasionally he will preform some trick that results in discomfort. He tends not to be interested in causing physical pain unless he is attempting to impress someone who values that characteristic.
Mental anguish and its manufacture in mortals is his speciality, though that particular skill is something that has fallen into disrepair in him over the years; he hasn't exercised his powers in mental manipulation and inducing insanity for centuries, and as such he is very much out of practice.
He is a very vain man, and loathes the idea of being what he classes an unattractive; the bodies he chooses always fit a certain profile in terms of looks, and he judges a child carefully before replacing it.
He is devoted when it comes to his idea of family, and is more than willing to go to great lengths for the sake of successful reproduction with his chosen spouse; to the extend of sacrificing a great deal of his own power and, temporarily, his chosen form.
He carries nothing save for a simple wooden flute, being able to magic up anything that he might need. He uses nothing in the way of weaponry, being a generally non-combative creature. Most of the items he creates are not what they appear to be; their face value often more impressive than their actual capabilities.
It is said that if you do not keep constant watch over your child, that if you forget the charms and wards to keep the fairyfolk away, then you might wake in the morning to find a changeling has come and replaced the babe you left to sleep.
Over several hundred years he has taken on many forms, one of which he declared as ugly and he has sworn to never inhabit an unattractive body again.
With the assistance of Absinthe, he stole the unborn baby from an unwitting woman and replaced it with a magically created stock, all for the final purpose of creating a child. However, lacking proper assistance from his partner, Trephan was unable to accurately steal the body of a young woman, Kate, to house his unborn child, and as a result the child was poorly formed and its father too weak to correct this.
Trephan was forced to take on a new body at once, chosen for the sake of connivance, and has yet to discover what became of his failed attempt at parenthood.