The black cat that appears in every episode of Trigun is called "Kuroneko Sama" (which means "Lord Black Cat". The cat is a female and was a creation for one of Yasuhiro Nightow's first mangas (Japanese comic books) and he has stated that the cat is female. Her alternate name is "Kuroneko Kukan" or "Black Cat Space". She also makes a cameo in the video game "Wild ARMs: 2nd Ignition".

Yasuhiro Nightow has gone on record to say that English is the language actually spoken on the Planet Gunsmoke.

For unknown reasons, the anime contains various fictional units of measurement. The three most prominent are "iles" instead of "miles", "yarz" instead of "yards", and "double dollars ($$)" instead of "dollars ($)".

The series is named Trigun because Vash has three guns. His revolver, his prosthetic arm which houses a gun, and his angel arm.

Knives and Vash are twins, that fact not only makes them both equal theoretically,_ but practically as well. In the beginning of the plot of the anime, Knives is shown to have upper hand in combat against Vash, but as the plot progresses and the final fight between Vash and Knives comes up, Vash is shown to have more dominance in the scene, contributing to the fact that Vash had fought different powerful enemies, while Knives simply commanded the 'powerful fighters' to kill Vash.