Shempire

The original script for The Trial describes the ’shempire’ that Darla tried to get to sire her:

Darla is seated in a booth at the back of this seedy bar. Across for her is a total SHEMP VAMPIRE (or “shempire”), he sports an eighties mullet hairdo. He bares his fangs and tries to talk all evil-sexy.

Doug Petrie

Doug Petrie was a co-executive producer, writer and director on Buffy. He also wrote the Angel episodes ‘The Trial‘ and ‘In the Dark‘. Doug is a huge fan of comics. He’s written several Buffy comics and worked on the screenplay for the upcoming Fantastic Four feature film. There are loads of comic book references in Doug’s episodes. He has also worked on Tru Calling, Harriet the Spy and Clarissa Explains it All.

The Valet

The Valet was the assistant for the trial Angel undertook in attempt to save Darla from dying in The Trial. An impartial and formal English man, he cryptically led Angel through the three levels of The Trial. When he realised that he was unable to save Darla, he apologised, saying she was already on her second chance.

Hey, it’s like a metaphor

The flower jasmine has been compared to vampires twice in the Buffyverse. In I Only Have Eyes For You:

Drusilla: “Wow! Look. Jasmine.”
Angelus: “Night blooming.”
Drusilla: “Like us.”

And then in Angel’s The Trial, Darla says of the jasmine in the courtyard at the Hyperion Hotel, “Hmm, jasmine. It blooms at night. I remember what that was like.” Season four’s entity Jasmine was named after the same plant looked at by Darla.

Anne Rice

Anne Rice was the author of a popular best-selling series of vampire novels, including Interview with the Vampire, The Vampire Lestat and Queen of the Damned. In School Hard, Spike says to Angel, “People still fall for that old Anne Rice routine?”
In Buffy vs Dracula, Buffy tells Dracula, “I’ve fought more than a couple pimply, overweight vamps that called themselves Lestat.” She’s referring to the main charismatic vampire character of Anne Rice’s The Vampire Chronicles.
The story in Lies My Parents Told Me of Spike siring his mother as a vampire may come from Anne Rice’s The Vampire Chronicles. In the book, the character Lestat sired his mother Gabrielle, because she was ill and to prevent her from dying.
When Darla tries to get a vampire to sire her in The Trial, they have the following conversation:

Darla: “Weird?! It’s mythic!”
Shempire: “No, you been reading too much Anne Rice, lady. You got no idea how this thing works.”

In Origin, Connor asks Angel, “Do you spend all your time making out with other vampires, like in Anne Rice novels?”