"Nocturne" is a Latin word derived from "nox, noctis" meaning "night". Nocturne can be loosely translated to "by the night".
In French, a nocturne is usually a musical composition that is inspired by, or evocative of, the night. Historically, nocturne is a very old term applied to Night Offices and, since the Mid Ages, to divisions in the canonical hour of Matins.
In French, nocturne is also an adjective to describe living entities who are active at night.
Umbra, the Latin word for "shadow", is the darkest part of the shadow, where the light source is completely blocked by the occluding body. An observer in the umbra experiences a total eclipse.
Nocturne was the first champion to be previewed on a popular event prior to its release, namely at the PAX East 2011.
He was also given a small sneak peek on the website IGN before release.
Nocturne's ultimate Paranoia was the name of Fiddlesticks' original passive, which caused enemies nearby to miss their attacks.
Nocturne along with Fiddlesticks' are the only champions that were featured in two special login screens.
One being the 2011 harrowing event, where the login screen was Nocturne in his Haunting skin, and when his legendary skin was released, Eternum Nocturne. (5 dec.)
Quotes
Nocturne's quote: "Afraid of the dark?" is similar to Cho'Gath's quote: "Afraid of the dark? Wise...".
Nocturne's quote: "Embrace the darkness!" might be a reference to The Darkness game.
Nocturne's joke: "Weather forecast for tonight: dark, with a chance of pain!" might be a reference to a George Carlin routine, "Al Sleet, the Hippy-Dippy Weatherman".
Eternum Nocturne joke "We have learned of spin to win, None can stop... it's a trick!" Is a reference to the popular League of Legends meme "Spin to Win"
Graves'sSmokescreen interacts with Nocturne. If an enemy Nocturne is hit by Smokescreen, Graves will say "I've got your darkness" or "Who's in the dark now?".
This was the first example of unique dialogue triggered by interactions between champions.
Frozen Terror Nocturne changes the particles of his Duskbringer and Unspeakable Horror abilities to light blue instead of the original's black.
Haunting Nocturne had its Duskbringer and Unspeakable Horror ability particles changed from the original's black to slime green after a petition on the League of Legends forum by players as seen here.
Eternum Nocturne changes the particles of his Duskbringer, Unspeakable Horror, Paranoia to a red colour instead of the original's black. Also Shroud of Darkness particle changes to a cleaner, bigger spell shield that resembles more Spell Shield than the classic version of this one.
Nocturne's appearance and abilities are also similar to Mercurial the Spectre from Dota.
Haunting Nocturne's art was used for the log in screen during The Harrowing of 2011.
Nocturne's general theme bears some resemblence to the NecronWraith and one of the Necron's Star Gods, the Nightbringer. This is particularly prevalent in his Eternum skin, where he also also draws some similarities to another Star God, the Deceiver.
Eternum Nocturne's color pallet and somewhat electronic spell effects resemble the Battlecast skins.
Eternum Nocturne's voice and demeanor are similar to Harbinger from the Mass Effect series.
More specifically, several of his quotes are similar to lines from the Reapers Sovereign and Harbinger, including:
"Their existence is a mistake." resembling Sovereign's "Organic life is nothing but a genetic mutation, an accident."
"We transcend time." and "What was, is, and will forever be."resembling Sovereign's "We have no beginning. We have no end. We are infinite."
"Fate cannot be averted." resembling Harbinger's "You cannot escape your destiny".
"The end of days draws near." somewhat resembling Sovereign's "The time of our return is coming."
"We are one." resembling Harbinger's "We fight as one." and Sovereign's "We are legion."
He also bears some resemblance to the Human-Reaper.