Hedwig was a female owl in the original Harry Potter. However, she became a bisexual, goffick, human male after getting reimagined by Tara.
Description
Tara decribes Hedwig as being a sexy "goffik bi guy!!!!!11" and had "bleched blond hair wiv blak streaks up 2 his ears and he wuz wearing goffik blak iliner, a blak Green Day shirt (it showed billy joel wiv bolnd hair since it was da eighties), blak congress shoes and black baggy pants".
Role in My Immortal
Hedwig first appeared in Chapter 41. He used to be in XBlakXTearX, but had to quit because he broke his arm.
He used to be in love with Satan, but they broke up. Ebony gets them back together by making them have sex while she films them with her iPod in an extremely disturbing sex scene. They are caught and sent to Dumblydore's office.
Hedwig is last seen in Chapter 42 in the office with Ebony, Satan, James, Serious, Snap, and Lucian. Satan and Ebony eventually head back to the future and Hedwig is never seen again.
Notes
If Tara is a troll, it's very likely that her unorthodox (to put it lightly) depiction of Hedwig might be a reference to Hedwig and the Angry Inch, a film and musical about a gay man who was forcibly made transgender. Given the description (blonde hair, musically interested), this might be the case, thus making "Hedwig" actually another crossover character.
If this Hedwig is that character, however, they are still 'canon raped', as Hedwig wasn't a goff and most certainly wasn't around in England in the 90's.
Also, Tara made a mistake with the Greenday shirt - the band's lead singer is called Billy Joe Armstrong, while Billy Joel is a completely different person.