The Book of Tarnis was the source from which Giles got information on the Monks of Dagon and Glory. It was written by Tarnis, who founded the Monks of Dagon in the twelfth century.

Willow dressed as Joan of Arc when going to a Halloween party in Fear, Itself. Joan of Arc is the patron saint of France. From a young age she thought she heard voices which she believed to have been sent by God. They told her to free France from the …

In Helpless, we discovered that Buffy’s father Hank took Buffy to the ice capades every year on her birthday (”Look, I know you guys think it’s just a big, dumb, girlie thing, but it’s not. I mean, a lot of those skaters are Olympic medal winners. And every year my …

In Revelations, Gwendolyn Post mentions several important texts which Giles does not have, including Hume’s Paranormal Encyclopaedia.

After discovering Giles’s girlfriend Olivia in Giles’ apartment in The Freshman, Buffy said to him, “OK, remember before you became Hugh Hefner when you used to be a watcher?” Hugh Hefner is the founder of Playboy magazine. His decadent lifestyle at the Playboy mansions is well known. Charisma Carpenter (Cordelia) …

Hostile Sub-Terrestrials (or HSTs as Buffy accurately guesses in Doomed) was the Initiative code name for vampires and demons. In Doomed, Riley says that the Vahrall demon is “not a capture, it’s a kill,” meaning that the Initiative don’t capture all their specimens alive for experimenting.

Hostile Seventeen was the Initiative’s code name given to Spike after they captured him in the episode The Initiative. Interestingly, Riley told Buffy in A New Man that he had captured or killed seventeen ‘Hostile Sub-Terrestrials’ (or HSTs, the Initiative name given to demons).
In Where the Wild Things Are, Spike …

Holy Water is water that has been blessed by a member of the clergy. Like other religious symbols (such as the crucifix) it burns vampires, and can even kill them if it touches them in large amounts. Holy Water has been used as a weapon occasionally in the Buffyverse. In …

The Holy Grail is supposedly the cup from which Christ drank at the Last Supper. It is considered to be extremely powerful and many quests took place to try and find it. The Grail is alluded to twice in Buffy the Vampire Slayer. In The Harsh Light of Day, …

In Intervention, Giles helped Buffy find out what’s more to being a slayer by taking her to the desert to meet a spiritual guide. He first had to do a ritual to temporarily transfer his guardianship of her to the guide. Giles said of his ritual, “I jump out of …

In After Life, a hitchhiker (a demon which travels through dimensions on the back of another) possessed the Scoobies. It followed Buffy when she was resurrected in Bargaining. The Scoobies researched different types of hitchhiker, which include Skaggmore demons, Trellbane demons, Skitterers, Large and Small Bone-Eaters. Willow realised that the …

In The Pack, Principal Flutie brought a piglet named Herbert to be the mascot of the school football team, the Razorbacks. Herbert was eaten alive by students who were possessed by the spirits of hyenas, including Xander.

Hell’s Offspring is a demon-related book belonging to Giles. Joyce spotted it in Bad Eggs, when she looked for Buffy in the library.

The town of Sunnydale stands on a Hellmouth, which is situated underneath the library of the local High School (and later the Principal’s office). The Hellmouth can be defined as a mystical portal between realities or as a gateway to other hell dimensions. Strange and mystical occurances, and demonic activity …

Tucker Wells attempted to ruin The Prom by setting hellhounds loose on the school. He trained them to hate formal wear and party music by forcing them to watch movies including Prom Night, Prom Night IV, Pump Up the Volume, Pretty in Pink, The Club, and Carrie. Giles says of …