Ghosts

Nearly Headless Nick was sentenced to death by beheading, however the executioner's axe was blunt so it took 45 chops, and his head is still not fully chopped of. In the Chamber of Secrets, Nick holds his 500th Deathday Party, and we find out that he would like to join the 'Headless Hunt' however he is not allowed due to the fact he is not entirelly headless. He gets paralysed by the Basalisk after another student saw the basalisks eyes through Nick. In the Order of the Phoenix, Harry talks to Nick about aferlife and death.

Ghost The Bloody Baron
Real Name Baron
House Slytherin
Date of Death N/A

The Bloody Baron is so named due to the fact he is covered in blood. When he was alive, he was in love with the Rowena Ravenclaw's daughter, Helena Ravenclaw. R. Ravenclaw, send the Baron to find Helena after she becomes fataly ill, as she know's he won't stop until he finds her. The Baron then violently stabs Helena when she refuses to go with him. He then takes the weapon he used and kills himself. He wears chains as a form of penitence. The Bloody Baron is the only person other than Dumbledore who can control Peeves the Poltergeist.

Ghost The Grey Lady
Real Name Helena Ravenclaw
House Ravenclaw
Date of Death N/A

The Grey Lady is Rowena Ravenclaw's (the Ravenclaw Founder) daughter. While she makes very few appearances in the Harry Potter books and films, she appears in the Deathlt Hallows and we find out quite a bit about her. When she was younger, she stole the Diadem of Ravenclaw from her mother, as she hopes to become more smarter then her. Helena then goes into hiding in the forests of Albania, and hides the Diadem in the hollow of a tree. When her mother was dying, she sent The Baron to find Helena knowing he wouldn't rest until he found her. Helena refused to go with him, so he kills her through a single stab to her chest. The Grey Lady tells Riddle this story after he charms it out of her, and later Harry when he is trying to destroy the hocruxes.

Ghost The Fat Friar
Real Name N/A
House Hufflepuff
Date of Death N/A

The Fat Friar is an extremly forgiving ghost, shown when the ghosts are discussing Peeves in the Philosophers Stone. The Fat Friar wants Peeves to be alowd to come to the welcome feast, and then in the Goblet of Fire, he wants to let him come to the Feast.