Ghosts are a common feature in many speculative fiction stories, from Harry Potter to Supernatural to Saga and a million things in between. They can be scary, or silly, or solemn, but they tend to have one thing in common: ghosts cling to the mortal plane because of some sort of unfinished business in our realm. Because of this, ghosts are often used in one of two ways in storytelling: either as a horror trope, to pop up and say boo and scare you, or as a way to teach the living characters something about themselves—namely, how to avoid the circumstances that led them to being a ghost. And while there can be something tragic or terrifying about the horror type of ghost, I think that ghosts are more effective as a storytelling trope when they’re used to teach a lesson.
Speaking of ghosts, can anyone explain why this creepy little fricker was so popular?
Spoilers for Hikaru no Go below the jump.
Of course, everything is contingent on how ghosts work in a given universe. In Supernatural, for example, ghosts are echoes of a person’s spirit tied to their physical remains on earth.
Furthermore, spirits only tend to stick around if they have some sort of grudge that they’ve carried into death. Generally, this grudge makes them desire revenge, and they become vengeful spirits. However, SPN’s ghosts rarely have the sentience that the being’s living self had; they’re more of a raw, angry nerve that lashes out at anyone who resembles the person they hate, whether that means a more specific category like “cheerleaders” or a more general one like “men” or “all human beings”. Because of this, ghosts have never been used in-show to teach greater moral lessons (like, “what defines humanity versus monsterhood?”) in the way vampires and other creatures have. They’re scary, and they can be difficult to defeat, but the only real lesson Supernatural’s ghosts can teach the living is to burn your dead friends’ remains—which isn’t exactly something you can translate into the real world.
Bleach is another series where ghosts are not used to their fullest potential. Soul reapers, the spiritual guardians of the earth, are tasked with two responsibilities: to send peaceful souls trapped on earth on to heaven, and to dispose of vengeful spirits, called Hollows, who have lost themselves to evil and who must be banished to hell.
Wasn’t kidding. It’s called a soul burial, and they boop ghosts on the head with the hilts of their swords.
While the series’s author, Kubo Tite, could have done something interesting with the peaceful ghosts, I often doubt that he even remembers that reapers are supposed to do both things. It is a shounen manga, after all; why spend time booping peaceful ghosts on the head when you could be beating up bad guys? There is an arc near the beginning of the story featuring the ghost of one of the main characters’ brother, but he, like the ghosts in Supernatural, goes full dark side as a Hollow because he is carrying so much resentment toward his sister, and has to be put down.
The Hollows as a vengeful spiritual force don’t really become interesting as movers and shakers of the plot until a few hundred chapters in, when they evolve into a superior and fully sentient form known as Arrancar. Once that finally happens, they manage to fill a fascinating middle ground where they are both the scary villains and the sort of spirit the characters and the reader can learn something from.
And then there’s Hikaru no Go. This manga/anime series follows a young boy named Hikaru who discovers a haunted go board in his grandfather’s house. Fujiwara no Sai, the spirit trapped in the board, killed himself back in the Heian era of Japan (800–1200ish CE) after an opponent falsely accused him of cheating and disgraced him in front of the Imperial Court. Since then, every time his go board is found, his spirit becomes tied to the finder. The person who finds the board is the only one who can see Sai, and Sai guides their moves in go games such that they become masters of the game. Through his living companion, Sai is able to continue to play the game he loves and progress toward finding a divine move, an “inspired and original move” that brilliantly balances all aspects of the game.
However, Hikaru at first doesn’t care about Sai’s centuries-old quest; he considers go an old man’s game and resents Sai for making him play it. As time goes by, though, Hikaru begins to develop his own skill in the game and starts to have disputes with Sai—he wants to play his own go (hence the title, which translates to “Hikaru’s go”) rather than simply placing the stones where Sai wants them to be. 
After an intense match with a highly-ranked professional, Sai begins to realize that his own selfishness was affecting Hikaru, and that perhaps the reason his spirit persisted was to guide the next generation in go rather than to pursue his own dreams. When he fades away, Hikaru is devastated at the loss of his mentor and friend, but finds solace in the game that Sai taught him.
Hikaru learns that even when people we love are gone, they still live on in the lessons they taught us and the actions we take. On the flip side, before his passing, Sai had learned that it was unfair to pile his own dreams and expectations onto someone else’s life. Because Sai, unlike Supernatural’s ghosts, is a fully sentient being and exists for reasons besides being 2spooky, he is able to both learn and teach over the course of the story.
A large part of why ghost stories like Hikaru no Go are more interesting, I think, is because the ghosts in these media are given full agency. A creature that lashes out without fully understanding why it is doing so, or which does violence for the sake of violence, is no better than an animal from a storytelling perspective. Characters like Sai or the many Arrancar-type Hollows have their own perspectives, hopes, and fears, and because of this, they have the potential to be actual characters rather than simply the spooky but two-dimensional villain of the week.
Lady Geek Girl and Friends 